LOOP SK03 Pro

Specifications

Brand/model LOOP SK03 Pro
LED Main light (Philips 6500K), Side lights (6*COB)
Maximum lumens 1,000 lm
Maximum beam intensity 3,600 cd
Maximum throw 120 m
Battery 1*14500, 1*AA Ni-MH
Onboard charging No (USB-C battery)
Material Aluminium
Modes Main Light (4), Side Lights (2)
Blinkies Main Light (Strobe, SOS, Beacon), Side Lights (Beacon)
Reflector Pebble TIR
Waterproof IP65
Review date June 2024

Introduction

The LOOP SK03 Pro is a futuristic-style of EDC torch with a multifunction bracket that acts as a package opener, bottle opener, magnetic mount and a fidget toy. Six electronic side emitters turn this thing into a mini lantern. And the included 14500 battery with USB-C charging helps complete the package.

LOOP GEAR is a relatively new brand by a small team of flashlight enthusiasts.

They made quite the introduction with the LOOP SK01s (a zoomable LEP)!

What is the difference between the SK03 and the SK03 Pro? The Pro version has a multifunction bracket!

Here is my video review of the LOOP SK03 Pro:

LOOP kindly sent this torch for review. I have not been paid for this review nor have I held back my opinions of this torch.

Packaging

The LOOP SK03 Pro comes inside a cardboard box. Inside the cardboard box is a transparent box with a LOOP SK03 sticker on the top and a few bags full of accessories (diffusers, o-ring, pocket clip).

LOOP SK03 Pro packaging LOOP SK03 Pro packaging

The following was included in the box:

  • LOOP SK03
  • Multifunction Bracket
  • Pocket clip
  • LOOP 14500 Li-ion 3.6V 920mAh USB-C rechargeable battery.
  • USB-A to USB-C cable
  • Spare o-ring
  • Diffusers (red, blue, yellow, gray)
  • User manual

LOOP SK03 Pro packaging

LOOP SK03 Pro accessories-1 LOOP SK03 Pro accessories-2

The user manual is small. LOOP included a larger A4 sheet of paper with instructions.

LOOP SK03 Pro user manual-1 LOOP SK03 Pro user manual-2

Torch in use

The SK03 Pro is lightweight and comfortable to hold. The stainless steel button and head look gorgeous!

LOOP SK03 Pro in-use-1 LOOP SK03 Pro in-use-2

The multifunction bracket has a sliding mechanism where a package/bottle opener tool can be pushed between a closed and open position.

The notch with a minus symbol (-) can be rotated 360 degrees and it allows the tool to be locked in a closed or open position.

To lock: rotate the symbol (|) so that it is perpendicular to the rest of the torch.

To unlock: rotate the symbol (-) so that it is parallel to the rest of the torch.

LOOP SK03 Pro multifunction-bracket-4 LOOP SK03 Pro multifunction-bracket-3

The package opener does an okay job at cutting through tape on a box. It is not sharp.

LOOP SK03 Pro in-use-3

There are two powerful magnets in the multifunction bracket. One is near the tip and the other is in that notch with a minus symbol.

The strong swivel joint and powerful magnets mean that the multifunction bracket is capable of holding the weight of the torch at an angle. It can be used a as work light!

LOOP SK03 Pro multifunction-bracket-1 LOOP SK03 Pro multifunction-bracket-2

There are six groups of three COB emitters around the side of the torch. These look like the electronic equivalent of tritium vials or glow sticks. But they can go from a dim firefly light to much more powerful High mode!

The side lights can be cranked up to High and the included diffusers can be added to change the colour.

The SK03 can also function as a small lantern!

LOOP SK03 Pro side-lights-1 LOOP SK03 Pro side-lights-2

LOOP SK03 Pro side-lights-3 LOOP SK03 Pro side-lights-4

There is a lanyard hole in the multifunction bracket.

The torch can tailstand on the button.

Build quality

The LOOP SK03 Pro has a matte black anodised finish. The head and button are stainless steel.

There are no sharp edges. The package opener is blunt. That said, I almost pinched my finger a few times between the multifunction bracket when swivelling it to the closed position against the body of the torch.

LOOP SK03 Pro front LOOP SK03 Pro right

LOOP SK03 Pro back LOOP SK03 Pro left

The multifunction bracket does clip securely to my pocket. There is about 2-3mm of play when pulling the bracket away from the torch before two ball bearings engage.

LOOP SK03 Pro multifunction-bracket-5 LOOP SK03 Pro multifunction-bracket-6

The multifunction bracket can be removed by unscrewing the tailcap. There are three screws that the bracket lines up with to keep it locked in one place. There is a bit of side-to-side-play.

LOOP SK03 Pro side LOOP SK03 Pro multifunction-bracket-7

The included reversible pocket clip does a much better job at being a pocket clip.

LOOP SK03 Pro pocket-clip

When I look at the button under a light I can see two fans of light spin outward from the laser engraved LOOP logo. It reminds me of a knob on a HiFi system. It looks so cool! And yes, the forward-clicky electronic switch gives a satisfying click.

LOOP SK03 Pro closeup-button

The tailcap is easy to line up and screw on. I noticed that the partially unanodised threads have become slightly gritty over time.

LOOP SK03 Pro threads

There is an inner tube for the signal. I like how LOOP used six pogo pins in the tailcap for the inner tube!

You can kind of mechanically lock the torch by slightly unscrewing the tailcap. It will disconnect the pogo pins and stop the button from working. But power will still flow to allow the Side Lights to remain on in a Micro Mode when a 14500 cell is used.

LOOP SK03 Pro tail-spring

There are two notches on the driver near the positive terminal for physical reverse polarity protection. RPP seems to work. It tried putting a flat top 14500 cell in and the torch did not turn on. I put the cell in backwards and the driver and cell were ok (don’t try this at home!).

It would be nice if the TIR optic had a glass lens to protect it.

LED, bezel, lens, reflector and beam

This particular LOOP SK03 Pro comes with a cool white Philips 6500K emitter. There is also a version of the LOOP SK03 available with a high CRI Nichia 519A 4000K emitter.

It looks like LOOP has tried to find a balance between a floody and throwy beam by using a pebble TIR optic with a bit of a fresnel lens pattern. This helps make the beam smooth and it provides a bit more beam distance.

LOOP SK03 Pro closeup emitter

There is no glass lens in front of the plastic TIR optic to protect it. A smooth bezel is holding the TIR optic down.

LOOP SK03 Pro closeup bezel

I asked LOOP about the bezel and they said that it has not been glued down. I used the underside of a mousepad to unscrew the bezel. And then I removed the o-ring from around the TIR optic to reveal the LED and a blue glow-in-the-dark ring.

LOOP SK03 Pro tear-down

CCT, CRI, and duv

I have taken Correlated Colour Temperature (CCT) and Colour Rendering Index (CRI, RA of R1-R8) measurements with the torch positioned one metre away from an Opple Light Master Pro III (G3). High (Side lights) was measured at twenty centimetres.

The CCT is around 5300K, the CRI is around 68 and the Delta u, v is positive (green) for the Main light.

The Main light is supposed to be a Philips 6500K emitter. But the CCT is closer to 5300K. Perhaps a different bin was used. This might explain the slightly lower than expected lumen output.

The beam produced by the Main light has smooth white hot spot, with a hint of green, blending into a purple spill with a flower pattern.

The CCT is around 5100K, the CRI is around 97, and the Delta u, v is slightly negative (rosy) for the Side lights.

The beam produced by the Side lights is very floody.

Main light

Cell Mode CCT (K) CRI (Ra) x y Duv
14500 Low 5241 69.5 0.3398 0.3731 0.0125
14500 Mid 5258 67.7 0.3393 0.3713 0.0119
14500 High 5315 67.9 0.3376 0.3693 0.0117
14500 Turbo 5428 69.0 0.3344 0.3645 0.0107

Side lights

Cell Mode CCT (K) CRI (Ra) x y Duv
14500 High 5102 97.0 0.3416 0.3373 -0.0059

Calculate Duv from CIE 1931 xy coordinates

Dimensions and size comparison

Dimensions

I took the following measurements using a digital caliper.

Measurement Unit (mm)
Length 76.5
Head diameter 21.5
Tail diameter 21.2
Tube inside diameter 14.32
Battery diameter 14.39
Battery length 50.3

Weight

I took the following measurements using a digital scale.

Weight Unit (g)
Torch 46.81
Bracket 24.93
Battery 19.50
Torch with bracket 71.74
Torch with bracket and battery 91.24

Size comparison with its competition

From left to right: LOOP SK03 Pro, Wurkkos TS10 TiCu, Lumintop FWAA TiCu, Manker E05 II Ti, Manker E05 II Copper, Manker E05 II Army Green, ReyLight LANapple, Acebeam Pokelit AA Ti, Acebeam Pokelit AA Gray, Acebeam Pokelit AA Copper

LOOP SK03 Pro, Wurkkos TS10 TiCu, Lumintop FWAA TiCu, Manker E05 II Ti, Manker E05 II Copper, Manker E05 II Army Green, ReyLight LANapple, Acebeam Pokelit AA Ti, Acebeam Pokelit AA Gray, Acebeam Pokelit AA Copper

From left to right: LOOP SK03 Pro, Wurkkos TS10 TiCu, Lumintop FWAA TiCu, Manker E05 II Ti, Manker E05 II Copper, Manker E05 II Army Green, ReyLight LANapple, Acebeam Pokelit AA Ti, Acebeam Pokelit AA Gray, Acebeam Pokelit AA Copper

LOOP SK03 Pro, Wurkkos TS10 TiCu, Lumintop FWAA TiCu, Manker E05 II Ti, Manker E05 II Copper, Manker E05 II Army Green, ReyLight LANapple, Acebeam Pokelit AA Ti, Acebeam Pokelit AA Gray, Acebeam Pokelit AA Copper

User interface

The LOOP SK03 Pro has a forward-clicky electronic tail switch to control the Main light and the Side Lights.

The Main light has four modes: Low, Mid, High and Turbo. And three blinky modes: Strobe, SOS and Beacon.

The Side Lights have three modes: Low and High. And one blinky mode: Beacon. There is also a special Micro mode when a 14500 cell is used.

State Action Result
Off Click Main Light On (mode memory)
On Click Off
Off Two clicks Main Light Turbo
On Two clicks Main Light Turbo
Off Three clicks Main Light Strobe
On Three clicks Main Light Strobe
Off Four to seven clicks Toggle Side Lights Micro (14500 only)
Off Eight clicks Lockout
Lockout Press and hold Main Light Momentary Mid
Lockout Eight clicks Unlock
Main Light Turbo Two clicks or hold Previous Main Light Mode
Main Light Strobe Hold Cycle Main Light (Strobe, SOS, Beacon)
Main Light SOS Hold Cycle Main Light (Strobe, SOS, Beacon)
Main Light Beacon Hold Cycle Main Light (Strobe, SOS, Beacon)
Main Light Strobe Three clicks Previous Main Light Mode
Main Light SOS Three clicks Main Light Strobe
Main Light Beacon Three clicks Main Light Strobe
Off Hold for 1 second Side Light On (mode memory)
Side Light On Hold Cycle Side Light (Low, High, Beacon)

Mode memory

Low, Mid and High are memorised for the Main light.

My understanding is that Strobe, SOS and Beacon are meant to be memorised for the Main light after performing three clicks from off and then by holding to cycle between Strobe, SOS and Beacon. However, I found that three clicks from off always goes to Strobe.

Low, High and Beacon are memorised for the Side Lights.

Strobe

Strobe appears to have a constant frequency.

14500 cell: Main Light (Strobe, SOS, Beacon), Side Lights (Beacon)

LOOP SK03 Pro strobe LOOP SK03 Pro sos LOOP SK03 Pro beacon LOOP SK03 Pro beacon

Ni-MH cell: Main Light (Strobe, SOS, Beacon), Side Lights (Beacon)

LOOP SK03 Pro strobe LOOP SK03 Pro sos LOOP SK03 Pro beacon LOOP SK03 Pro beacon

I measured Strobe, SOS and Beacon of the light with a Zoyi ZT-703S oscilloscope using High Speed mode.

Low voltage protection

There is low voltage protection when using a 14500 Li-ion cell.

I tested low voltage protection by connecting the head of the torch to a bench power supply and then by lowering the voltage from 4.2V to 0V to simulate a 14500 Li-ion cell.

LED Cell Mode LVP? Cut-off
Main 14500 Low Yes 2.80V
Main 14500 Mid Yes 2.80V
Main 14500 High Yes 2.80V
Main 14500 Turbo Yes 2.80V
Side 14500 Low Yes 2.80V
Side 14500 High Yes 2.81V

There appears to be low voltage protection when using a Ni-MH cell. I have not tested this with a bench power supply.

The torch turned off at the end of runtime tests while using 14500 Li-ion and Ni-MH cells as expected.

What I like about the UI

  • The UI is relatively simple to learn for a flashlight enthusiast.
  • Shorcut to Turbo from off.
  • Shortcut to Strobe from off.
  • Electronic lockout mode.

What could be improved

  • A Moonlight (<1 lumen) mode would be nice.
  • A shortcut to Moonlight or Low from off would be nice.

Batteries and charging

Battery

A LOOP 14500 3.6V 920mAh Li-ion battery with built-in USB-C charging was included.

LOOP SK03 Pro battery-1 LOOP SK03 Pro battery-2

A piece of insulating film was included to prevent the torch from being turned on while in the packaging.

LOOP SK03 Pro closeup-insulating-film

I tried the following cells:

Cell Top Compatible? Comment
LOOP 14500 Li-ion 920mAh 3.6V USB-C Button Yes
Acebeam ARC14500 Li-ion 920mAh 3.7V USB-C Button Yes
Manker 14500 Li-ion 920mAh 3.7V 4A CDR USB-C Button Yes
Vapcell H10 14500 Li-ion 1000mAh 3.7V Button Yes
Shockli Orange 14500 Li-ion 1000mAh 3.7V Flat No Physical reverse polarity protection prevents flat top cells from working.
eneloop pro AA Ni-MH 2450mAh 1.2V Button Yes
LADDA AA Ni-MH 2450mAh 1.2V Button Yes

Charging

Power supply: PinePower Desktop USB-C
USB Meter: AVHzY CT-3
Room temperature: 15 C

LOOP SK03 Pro charging profile

I charged the included battery from 3.02V to 4.15V using the battery’s USB-C port.

It took about 2 hours 40 minutes to fully charge at a rate of 5V 0.4A.

The indicator LED near the button top went red while charging and it went blue when charging was complete.

LOOP SK03 Pro charging profile LOOP SK03 Pro charging profile

Power supply compatibility

I tried the following power supplies with the built-in USB-C charger:

Power supply USB Type Protocol Does it charge?
Apple 61W Power Adapter USB-C PD Yes
Google Pixel Power Adapter USB-C PD Yes
PinePower Desktop USB-C PD Yes
PinePower Desktop USB-A QC Yes
PinePower Desktop USB-A Yes

USB-C to USB-C charging works.

Performance

Specifications from the user manual:

Main light Turbo High Mid Low Strobe
Output (lumens) 1,000 + 220 220 70 7 1,000
Runtime 30s + 2h 30min 2h 35min 10h 50h
Beam Distance (metres) 120
Beam Intensity (cd) 3,600
Side lights High Low Beacon Micro
Output (lumens) 80 10 10 0.1
Runtime 10h 50h 2 years

The specifications are for a LOOP SK03 with a Philips 6500K emitter and a LOOP 14500 cell.

I used an LADDA AA Ni-MH 1.2V 2450mAh cell and the included LOOP 14500 Li-ion 3.6V 920mAh cell for the following tests.

Lumen measurements

Note: Lumen measurements may be off by 10% with my DIY lumen tube. Output measured from TIR optics may be lower than normal with my lumen tube.

I used a UNI-T UT139C Digital Multimeter to measure the current at turn on.

Cell Mode Amps at start Specs Lumens @turn on Lumens @30 sec Lumens @10 min
14500 Low 0.02 A 7 8.5 8.5 8.5
14500 Mid 0.21 A 70 70 71 66
14500 High 0.51 A 220 176 165 161
14500 Turbo 2.00 A 1,000 + 220 792 568 162
Ni-MH Low 0.05 A 8.5 8.5 6.8
Ni-MH Mid 0.25 A 48 46 44
Ni-MH High 0.67 A 118 118 116
Ni-MH Turbo 1.55 A 191 113 116

Standby drain

I used a UNI-T UT139C Digital Multimeter to measure the standby current.

Cell Side Lights Current
14500 Off 60.5 µA
14500 Micro 60.5 µA
14500 Low 16.7 mA
14500 High 224 mA
Ni-MH Off 82.0 µA
Ni-MH Low 28.9 mA
Ni-MH High 180.3 mA

Runtime graphs

I used my own DIY lumen tube with a TSL2591 sensor and forked bmengineer’s project RuTiTe to record runtimes.

The room temperature was approximately 13 C.

LOOP SK03 Pro runtime graph

LOOP SK03 Pro first 3 hours runtime graph

LOOP SK03 Pro first 10 minutes runtime graph

Runtime

Here is a summary of the runtime results:

LED Cell Mode User manual Runtime Turn off Final voltage
Main 14500 Turbo 30s + 2h 30min 2h 21min 28s 2h 26min 16s+ 3.15
Main 14500 High 2h 35min 2h 30min 37s 2h 30min 37s+ 3.14
Main 14500 Mid 10h 6h 50min 33s 6h 50min 33s+ 2.94
Main 14500 Low 50h 10min+ 10min+
Main Ni-MH Turbo 3h 26min 5s 3h 56min 38s 1.15
Main Ni-MH High 3h 23min 40s 3h 56min 12s 1.14
Main Ni-MH Mid 10h 8min 25s 10h 8min 25s
Main Ni-MH Low 10min+ 10min+

“Runtime” is the time until the output reduces to 10% of the output at 30 seconds (as per the ANSI/PLATO FL1 2019 Standard).

“Turn off” is the time until my DIY lumen tube no longer detects more than one lumen.

“+” indicates that the light remained on after recording had stopped.

The runtime (6h 50min 33s) was shorter than expected for Mid mode with a 14500 cell. The torch continued beyond the advertised 10 hours but it did so with an output below one lumen.

The rest of the runtimes that I tested were pretty close to the advertised claims.

The output looks well regulated and constant when using a Ni-MH cell.

Output gradually drops over time when using a 14500 cell.

You may get a higher sustained output for EDC use with Turbo or High while using a Ni-MH cell.

Throw

I took lux measurements with a UNI-T UT383BT at 30 seconds. Low, Mid and High were measured at one metre. Turbo was measured at five metres.

LED Cell Mode Specs (cd) Specs (m) Candela measured (cd) Distance (m)
Main 14500 Low 21 9
Main 14500 Mid 233 30
Main 14500 High 574 47
Main 14500 Turbo 3,600 120 1,850 86

Pulse Width Modulation

There is PWM but I did not notice any visible PWM (flickering).

I measured the PWM of the light with a Zoyi ZT-703S oscilloscope.

14500 cell: Main Light (Low, Mid, High, Turbo), Side Lights (Low, High)

LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM

Ni-MH cell: Main Light (Low, Mid, High, Turbo), Side Lights (Low, High)

LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM LOOP SK03 Pro PWM

I have used a vertical scale of one volt and a horizontal scale of fifty microseconds to align with the scale used by zeroair.

Beamshots

I went to a local park and aimed the LOOP SK03 Pro at a tree 70 metres away.

Beamshots were taken using a Sony RX100M2 using 3.2", f3.2, ISO 100, 5000K WB.

LOOP SK03 Pro (Turbo)

LOOP SK03 Pro Turbo beamshot

Manker E05 II (High)

Manker E05 II High beamshot

Lumintop EDC15 (Turbo)

Lumintop EDC15 Turbo beamshot

Acebeam Pokelit AA Gray (High)

Acebeam Pokelit AA Gray High beamshot

Acebeam Pokelit AA Ti (High)

Acebeam Pokelit AA Ti High beamshot

ReyLight LANapple (100%)

ReyLight LANapple 100% beamshot

Conclusion

The LOOK SK03 Pro is a must have for flashlight enthusiasts!

It is a futuristic looking fidget torch with practical features bolted on.

The E Tritium Vials are a pretty cool electronic alternative to actual tritium vials (hard to find!).

The lumen output and beam distance were lower than expected. I suspect that a 6500K emitter may not have been used. I measured 5300K.

I would highly recommend a SK03 with a high CRI Nichia 519A 4000K emitter instead. Some enthusiasts have already removed the bezel and swapped the 6500K emitter out.

The runtime results were pretty good and the output is very stable when using a Ni-MH cell. Mid mode with a 14500 fell slightly short when adhering to ANSI/PLATO FL1 2019.

Pros:

  • Good build quality.
  • Good size for an EDC torch.
  • Multifunction bracket is cool and fun to play with!
  • The Main light output is very stable with a Ni-MH battery.
  • The Side Lights are a nice electric alternative to tritium vials.
  • The Side Lights have a high CRI.
  • 14500 Li-ion cell with USB-C charging included.

Cons:

  • The Main light has a low CRI.
  • The colour temperature of the Main light is warmer than expected (5300K instead of 6500K).
  • The lumen output of the Main light is lower than expected.
  • The beam distance of the Main light is lower than expected.

Price

The LOOP SK03 Pro is US$119.98 at loopgear.com (affiliate link)

The LOOP SK03 (not Pro) is US$59.99 at amazon.com (affiliate link)

Product page

LOOP SK03 Black at amazon.com (affiliate link)

LOOP SK03 Gray at amazon.com (affiliate link)

LOOP SK03 Pro at loopgear.com (affiliate link)

I may earn a commission if you use an affiliate link or a promo code. This will help fund future torch reviews and tutorials.