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CustomDUO modules

Fitting CustomDUO Gecko modules is quick and easy. Gecko modules will work with any Petzl Duo (excluding the new 2018 versions which are factory sealed and not designed to be upgradeable in the future as LEDs advance). Note, prior to fitting it is of course necessary to remove original reflector, bulbs, LED modules, etc.




Batteries, power and light output 

As standard, the Petzl Duo uses 4xAA batteries.  For best result we suggest low self discharge NiMh batteries, such as the 'Eneloop' brand.


The regulated power settings levels for modules are given in mA. To determine the approximate regulated duration of light on your battery arrangement at a given power setting, simply divide the mAh capacity of your cell pack by the mA power draw at a given setting. For example, using 2100mAh NiMh low self discharge AA batteries at a power setting of 350mA will give a regulated duration in the region of 5-6 hours. 




Occasionally we come across an early (pre 2004) Petzl Duo which has been wired up back to front, and the polarity is wrong for the Customduo LED modules. This affected some, but not all early Duos, and these Duos are now rare. Polarity conscious LEDs hadn't been considered at this time so it wasn't important which way around the positive and negative were wired at manufacture. If you fit your CustomDUO module and it does not immediately work, chances are that your Duo is wired up back to front. The solution is simple. Reverse the batteries in the battery holder, i.e. positive to negative, and vice versa. The module will then work. CustomDUO modules are polarity protected, so you will not have damaged the module by finding this out.




To complete fitting, refit the Duo front window. Holding window in position with thumb, refit the grey plastic bezel until the Petzl correct fitting alignment marks (on top of the lamp) are correctly orientated. The marker formed on the grey screw bezel needs to be somewhere in between the two markers formed on the top of the yellow moulded lamp body. 

Gecko 'Spot' Modules (pre 2018) are connected via a screw in bulb base, normally used by the conventional halogen bulb being replaced (for ease, screw in with the zoom feature in the forward orientation).  Once screwed in, the zoom feature for halogen bulb should be retracted and remain so. The Gecko Spot has a fixed focal reflector and therefore the Duos' zoom feature is now redundant. Once the bulb base is inserted, orientate the module to keep red and black wires seperate. This is a good time to power up the module and check that it is working and that the polartity of your Duo is normal!



If it doesnt work immediately, see notes on battery polarity below. Some (but not all) early pre 2004 Petzl Duos were wired to the opposite polarity, but it's very easily solved.


Gecko 'Side' Modules are a simple push fit. Electronic connection is via the 2 pins on reverse of module which locate in the Duo bi-pin bulb / LED connection socket. Orientate module in the body of your Duo, aligning the contact pins, and push fit module into place. Test operation of module. If module does not work immediately, then as above, see notes on battery polarity. Some (but not all) early pre 2004 Petzl Duos were wired to the opposite polarity, but is very easily solved.


Gecko Side module fitted with original halogen, reflector retained (14 LED reflectors do not require modification. 5 LED and bi-pin reflectors will require modification if used with halogen)

Gecko fitting guide