Sofirn IF25A

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Brand/modelSofirn IF25A
CategoryEDC flashlight
LED4 * SST20
Lumens3800 Lumens
Beam intensity/distance420 meters
Battery config.1*21700
ReflectorTIR optics
Review dateNovember 2020


Sofirn have listened to enthusiast feedback and produced a follow up to their IF25. The IF25 had tint ramping, which allowed you to fade between cool white and warm white. The updated version sacrifices the tint ramping for more lumens and the Anduril user interface. 

The IF25A is available with either 4000K (warm) or 6500K (cool) LEDs. This review is of the cool white IF25A, which has more lumens than the warm white one.

The IF25A is a small but powerful budget light. It takes a 21700 cell and has 4 SST20 LEDs, pumping out up to 3800 lumens. It also has USB-C charging built into the light.

Package quality.

The IF25A comes in a printed cardboard box. I received the “kit” version, which includes the cell and a few extras:

  • Sofirn IF25A flashlight
  • 4000mAh cell (some shop listings show a 4800mAh cell)
  • a 65mm long 18650 to 21700 sleeve
  • Manual
  • USB-A to USB-C cable
  • Lanyard
  • Spare O-rings

Handling of the light

The IF25A has bumps on the body, which make it easy to grip. You should be fine with gloves on, despite it not having knurling.

There’s no pocket clip with the IF25A but it comes with a (sharp!) lanyard hole. The lanyard hole is on one edge and still allows tail standing.

Without a clip though, it either needs to be loose in a pocket or in a pouch with a belt clip. That makes it not quite as good for EDC. There’s a couple of places on the body that a clip could go but you’d need one that stretched to 25.4mm. The IF25A would fit in a pocket if you’re used to carrying large 18650-sized lights.

Without a clip and with a fairly round, smooth body the IF25A rolls quite a bit when on a table.

The IF25A is pretty small for a 21700 light and is the shortest one I’ve seen. It’s shorter than Sofirn’s SC31B and SP40, both of which are 18650 lights

The e-switch feels solid – not mushy and not too hard. There’s no magnet in the tailcap. You may just be able to fit a small magnet in but there’s not lots of room.

Build Quality, Knurling, Threads, and anodization

The IF25A is well machined but it has sharp corners on the fins and lanyard hole. This hasn’t caused any issues with daily use but doesn’t feel as high quality as other lights, including some of Sofirn’s. The rest of the body is chamfered nicely.

The shiny black aluminium anodising looks good quality. If you attached a clip then it shouldn’t scratch the light. The threads are Sofirn’s usual good quality and are square cut and lubed.


Sofirn offers the IF25A with either 4000K or 6500K SST20 LEDs. 6500K is very cool for my liking, so I’d recommend the 4000K version. 

The IF25A uses 4 TIR optics instead of 4 reflectors. This means the light can be shorter and seems to help make a smoother graduation between hotspot and spill. There’s a few beam artifacts when shining at a white wall but this isn’t noticeable in normal use. 

On my one the bezel unscrews and allows access to the MCPCB under the glass and TIR. Others have reported the bezel being glued down. You can also take the optic out, and put the bezel back on, which changes the light into an almost 180° wide angle mule, which is great for indoor use. With the optics back in, the light is fairly throwy for a small multi emitter light.

The bezel is flat and thick, at a chunky 4.4mm


  • Length: 10.64 cm / 4.19 inches
  • Head diameter: 3.5 cm / 1.38 inches
  • Body diameter: 3.1 cm / 1.22 inches at its widest, 2.54 cm / 1.00 inches at its narrowest
  • Inner body diameter: 2.2 cm / 0.87 inches


  • Without cell: 99 grams / 3.49oz
  • With cell: 165 grams / 5.82 oz

Size comparison

Here’s the IF25A compared to some other popular flashlights. From left to right: Emisar D4, Sofirn IF25A, Sofirn SC31B, Sofirn SD05. The IF25A is not much longer than the D4, which takes 18650 cells.

Driver & User Interface:

The IF25A uses Anduril. Sofirn has used a slightly older version of Anduril, so doesn’t have a few of the newer features like showing the build version or the dual moonlight modes. There doesn’t seem to be easy access to the driver (at least with my skill level) if you wanted to update it.

As with most Anduril lights, there’s thermal throttling that might need configuring with a special series of clicks. Otherwise it may step down from turbo too quickly or too slowly. Mine said its room temperature was 26°C when it was actually 21°C.

From OFF:

  • Single-click: ON
  • Double click: High (Top of ramp)
  • 3 clicks: Access the blinky/utility modes.

Enter Special/Fun modes from OFF:

  • 2 clicks + hold: Strobe modes
  • 4 clicks: Lock Out mode
  • 5 clicks: Momentary on
  • 6 clicks: Muggle mode

From ON:

  • Single-click: Off
  • Double click: Turbo
  • 3 clicks: change ramping mode.. Instead of a smooth increase, it has 6 little steps between Lowest and Max.
  • 4 clicks: change to ramping configuration mode
  • Press and hold: brightness ramps up.. release and press and hold again to ramp down.


Please read the manual carefully to know how to access or customize these modes. Also see the firmware picture, above.

  • Blinky Utility mode:
  • Battery check
  • Sunset Mode
  • Beacon mode
  • Temperature check

Strobe / Mood modes:

When in the strobes mode, double-click to rotate between them – all modes except party strobe are brightness, changed the same way as a normal ramp. In party strobe mode, ramping up and down will increase and decrease the frequency of the strobe, for incredible effects.

  • Candle
  • Bike flasher
  • Party strobe
  • Tactical Strobe
  • Lightning mode
  • Lockout mode (can’t use the light)
    • Lockout mode is available by clicking four times from off – while in lockout mode, click-and-hold will light up at bottom of the ramp, and a double-click-and-hold will light up somewhat brighter. This is to give you a way to quickly use the light if necessary, but if it activates in your pocket, it will only be at very low modes, and only for as long as the button is pressed. No more holes in pants!
  • Momentary mode (signaling/ morse coding)
  • Muggle mode: (safer for children)
  • Configuration mode
  • Ramp config mode


  • You will be able to detect some PWM at low modes via phone camera, but as soon as it kicked in higher, it disappears. None of it was able to be detected by eye, though.

Protection Features (Low Voltage Protection)

  • LVP makes the light step down to a lower level when the battery is low, and if the light is already at the lowest level, it shuts itself off. This activates at 2.8V. LVP happens suddenly but you will notice a dramatic low output before this will happens.
  • Thermal regulation attempts to keep the light from overheating, and otherwise adjusts output to stay as close as possible to the user-configured temperature limit. Thermal adjustments happen gradually, in steps so small they are difficult for humans to perceive.

Troubleshooting ( Factory reset)

If you changed a setting accidentally and don’t know how to solve it, you can simply use the Reset function to go back to factory settings.

  1. Turn the light off
  2. Unscrew the tailcap
  3. Press and hold the switch for 3 seconds while you tighten the tailcap.

Batteries & Charging

Update: the new IF25A now works with USB-C to USB-C charging.

My IF25A came with a Sofirn-wrapped 21700 cell rated 4000mAh.

The IF25A has a medium-thick spring on the tail end and a flat connection on the head end. That means that 21700 cells fit in well and don’t lose connection when the light is knocked. Longer 18650 cells (button top or ones with protection or circuit) are fine too but I found a flat top 18650 (VTC5A) would lose connection when the IF25A was shaken. 21700 a couple of mm longer should fit too but I didn’t have any to test. I’d recommend button top 18650 cells or any 21700 cell for this.

The white sleeve to convert 18650 to 21700 width is also a bit loose in the IF25A and you can hear it move around a bit when shaken or tilted. A bit of paper between the sleeve and light fixes this.

Sofirn IF25A comes with built in USB-C charging under a rubber cover. The cover seems fairly good but as with nearly all built in charging, it’ll make the light less waterproof.

The IF25A lacks the circuitry to support the use of a C-to-C charging cable, so needs an A-to-C one. I measured the IF25A charging at up to 1.3A. The e-switch lights up red when charging and green when done.

You can also power the light via USB, though not to maximum brightness. The red indicating light comes on when you do this, to show it’s taking current from the charger. I noticed that Anduril’s candlelight mode flickered the green and red indicating light when USB powered, to make a nice orange colour. This might be a bug that turned into a feature.


All lux measurements are from my home made integrating box and Android lux meter (Moto Z3 Play), indoors and without any active cooling. Relative measurements will be accurate but absolute values may be +/-15% due to my setup. Current readings were taken with a Precision Gold PG10B DMM.

For the IF25A, I used Sofirn’s provided 4000mAh 21700 cell at full charge. Thermal config on the IF25A was reset at room temperature and set to 55 degrees limit. Measurements are on the default stepped mode, with 7 levels plus turbo.

Amp measurement

  • 1: 0.01A
  • 2: 0.08A
  • 3: 0.21A
  • 4: 0.46A
  • 5: 0.91A
  • 6: 1.68A
  • 7 (ramp ceiling): 2.63A

On turbo the light was pulling over 6A, though would likely draw more without my DMM setup. 

Runtime graph


On turbo, the IF25A hit 3018lm and stays above 2000lm for 2 minutes, dropping down to 1000lm after another 3 minutes. It measured 2773lm at 30s.

The thermal throttling took the output all the way down to 147lm for a few minutes, before ramping back up to sustainable levels. Output fluctuated quite a bit, staying around 400-600lm. This isn’t noticeable to the eye, so shouldn’t be a problem.

LVP kicked in after 2h40m and stayed around 10lm until I stopped recording 20 minutes later. The cell measured 3.04V after 3 hours.

Ramp ceiling

The highest normal mode behaves similar to turbo, though doesn’t step down quite as far. I left the light on overnight to test the LVP and it eventually dropped down to 1lm, with the cell at 2.97V.

Lumen measurements

Lumen measurements were taken at 30s, with Sofirns cell fully charged, unless otherwise stated

  • 1: 8lm
  • 2: 39lm
  • 3: 104lm
  • 4: 236lm
  • 5: 566lm
  • 6: 1070lm
  • 7: 1719lm at startup then 1578lm @ 30s
  • turbo:  3018lm at startup, then 2773lm @ 30s
  • turbo: with Samsung 30T cell 4423lm at startup, then 3624lm @ 30s

Throw numbers

Lux was measured at 5m.

  • 602 lux @ 5m = 15050 cd = 245m

Sofirn’s official specs list 420 meters for the IF25A, which I have trouble believing. I expect this to be a typo – perhaps they meant 240m. The IF25A has similar throw to an Emisar D4, which is around 250m, depending on the LED.


Beamshots are taken on a Pixel 3a with exposure 1/4s, ISO 1600, 5000K.

The red construction material and tree in the centre are around 60m. You can just see concrete posts on a fence up to 75m away.

Sofirn IF25A SST20 6500K

Emisar D4 XP-L Hi 4000K

Sofirn SC31 Pro SST40 6000K-6500K

Disclaimer: This flashlight was sent to me for review at no cost, by Sofirn. I have not been paid to review, nor have I been holding back on problems or defects.



  1. Bright at 3800lm with a good beam profile
  2. Built in USB-C charging
  3. Compact size for a 21700 light
  4. 4000K tint option available


  1. Some sharp edges
  2. No pocket clip
  3. Anduril version is fairly old
  4. No support for C-to-C cables (Update 2021: they now do)
Reviewer Dave
Author: Dave

5 stars: ★★★★★

The Sofirn IF25A has a few minor issues but they’re balanced out by the power, capabilities and features of the light. The built in charging is great and makes the IF25A easy to recommend. Ultimately it won’t replace my D4 as my EDC due to lack of a good clip. For its price, the IF25A is hard to beat.

Sofirn IF25A for sale

1lumen selects and reviews products personally. We may earn affiliate commissions through our links, which help support our testing.