Pocket Illumination.

Compact, efficient, versatile. We built this to be our most compact 21700 flashlight with an all-new sculpted design. Paired with the unparalleled Lume X1 boost driver electronics, the X4Q Comet is your everyday flashlight companion. 

For 2025, we've refined the body of our most compact 21700 flashlight for a more tactile grip, improved the tail magnet strength, and refined the pocket clip to be stronger and more durable.

Photograph of Comet C/2023 A3 (Tsuchinshan-ATLAS) together with Fireflies Comet X4Q FFL351A 4000K (photography by Loneoceans).

Features

• Compact Size - 108mm x 30mm x 25.5mm 
• Weight - 85 gram (without batteries)
• Quad 3535 LED Emitter Configuration
• Battery - unprotected flat-top 21700 (not included, recommended to use high-drain cells including Molicel P42, P45, P50, or Samsung 40T, 50S, or Vapcell T50)
• RGB Auxiliary (front), Illuminated RGB Side-Switch
• CNC Construction, 6063 Alloy, Stainless Steel Bezel and Switch
• Optics - 15-deg middle-range TIR (default), 30-degree frosted TRI (included)
• Open-Source Anduril2 User Interface / Firmware
• Lume X1 40W Boost Driver, Constant Current Regulated (up to 95% efficiency) with UDR (Ultra Dynamic Range)
• Automatic Thermal Regulation, Low Voltage Cut-off, Reverse Polarity Protection
• Improved Be-Cu Beryllium Copper Silver-Plated Springs
• Toughened Front Glass Lens, AR Coated (~98% transmittance) 
  
• Magnetic Tail Cap (user-removable)
  
• Water Resistance - IPX8
• Drop Resistance - 2m

Included Accessories 

• 1x Stainless-Steel Clip
• 1x Additional 30-degree frosted TIR optic
• 1x SS Lanyard ring
• 1x Lanyard
• 1x Tail Magnet
• Spare O-rings

Emitter Specifications

User Interface: (Anduril V2)

This flashlight uses the open-sourced Anduril user interface. Anduril 2 is an open-sourced software and distributed under the terms of GPLv3. The source can be accessed here. 

By default, this flashlight begins in Simple UI with 5 brightness levels. Enter the hidden Advanced UI to access additional features and more configuration options.

Details can be found in Anduril User Guide. 

Battery Level Indicator

Anduril2 UI uses the front RGB auxiliary LEDs to indicate the current battery level upon turn-off. The colors correspond as follows:

This post-off display can be turned off or configured in Anduril. 

Operation Notes

• X4Q Comet is a high-performance flashlight capable of up to 40W and generates a lot of heat. Please understand that this is not a toy and should be handled with safety.
• X4Q Comet uses the high-performance Lume X1 driver. For best performance, use high-drain unprotected flat-top 21700 cells only. Recommend cells include Molicel P42, P45, P50, or Samsung 40T, 50S, or Vapcell T50. Please handle cells with care.
  
• Batteries and external charger are not included.
• To prevent accidental activation of the flashlight, it is recommended to lock-out the flashlight (4 clicks from off to lock or unlock) before storage or unscrew the body a quarter turn as a mechanical lock-out. 
• This flashlight has low-voltage protection which cuts off power at 2.8V. It is recommended to begin recharging the cell before this happens to increase battery longevity. 
• The Lume X1 driver (Rev B with AVR32DD20 MCU) features UPDI flashing pads for advanced users to perform their own firmware updates or to flash custom firmware binaries.