CustomDUO modules

v42 (r02)

Now Available

Latest v42 (r02) and Simple (r02)

v42 reviewed (r01)

The v42 is the latest version of our widely acclaimed Duo Omni module, simply the most effective LED conversion for the Petzl Duo, with user programmable light settings. The spot and flood LEDs can be operated separately, or blended together, to to best suit your individual needs. New features for the r02 revision include our innovative new integrated alloy heatsink, and 5 green indicator LEDs for battery charge level.



v42 (r02) Specification 

  • Will work with any original pre 2018 Petzl Duo - the Cavers Duo!
  • Integrated alloy heatsink design
  • Twin high power XP-G3 LEDs (172 lumen @ 350mA @ 85 degC) 5000k neutral - cool white
  • Also available with 4000k neutral - warmish XP-G3 LEDs (172 lumen @ 350mA @ 85 degC)
  • 620 lumen maximum output (combined spot 310 lumen and flood 310 lumen)
  • 4 useful regulated light settings (factory default - see table below) 
  • User configurable settings, easily programmed with remote control
  • Smooth spot optic for distant focus, and flood LED with efficient optic
  • LEDs operated separately or blended together, from 25 lumen
  • User defined power combinations to best suits your individual requirements
  • Low power moon setting (8 lumen)
  • Battery charge indication using 1-5 green indicator LEDs
  • Super robust, proven circuit architecture
  • Discreet thermal management to protect LEDs !!
  • Simple push fit directly into existing Petzl Duo pilot bulb connection, see Fitting Guide 
  • No power drain on batteries when lamp is switched off
  • Progressive dimming at end of battery charge (will not just shut off when batteries are flat)
  • 6.0 volt maximum input (4x AA batteries) 
  • Well suited to 3.7v li-ion battery conversion (battery charge level indicator can be set for li-ion)   

The v42 has two main LEDs. A focused spot LED and a wide angle flood LED with optic.  In normal operation the v42 has four factory default power settings (see following table). The v42 also has 5 green smd indicator LEDs for battery charge level indication. Main LED also blinks 1-5 times, visible without removing helmet.

The factory default light settings are;


  1. low flood - hands and knees caving !
  2. high spot - route finding in  large passages
  3. medium flood - general progression around cave
  4. high spot and high flood - if you really must !!


see Operation chart including light output and indicative run times

To switch between the settings, use the down switch on the Petzl Duo. Switch on-off-on-off to move between settings 1-2-3-4 ... 1-2 etc, in a looping sequence. Setting 1 will blink momentarily when selected to make it very easy to determine exactly which setting has been selected. 

Operating the switch very quickly, on-off-on ('double switch') will operate moon (camp) setting for maximum run time. At this point, the 5 green indicator LEDs with show battery charge, and the main LED will blink 1 to 5 times to indicate the approximate level of battery charge.  This is visible without removing helmet for maximum convenience.

The v42 can be programmed using Customduo infrared remote control (cr2025 battery required). From 1-9 light settings can be specified, and the level of light provided by the spot and/or flood LEDs for each setting can be configured by the user. This is now even easier as the 5 green LEDs provide feedback!


The spot and flood LEDs can be operated separately or blended together. Each LED can be operated at low, medium, medium plus, high and maximum, offering a choice from 24 possible light combinations 

For further information about operaton and performance, including how to program and configure settings, see v42 (r02) Operation 

Factory Setting

Spot LED

Flood LED


(5000k LEDs)


(3000k LEDs)


(est. 2500mAh eneloops)

1 (low flood)



73 lumen

65 lumen

16 hours

2 (high spot)



310 lumen

280 lumen

3 hours

3 (medium flood)



172 lumen

156 lumen

7 hours




620 lumen

560 lumen

1.5 hours




8 lumen

8 lumen

100 hours