Nitecore D20

The D20 is a little special due to its piston drive...

I don't own one, but I am a collector of EX10 and D10, the one-cell versions of the piston drive lights. The D20 didn't sell well, as it seems people don't want two cells with piston drive, but what I heard the light is of good quality and has a nice beam.

An explication for the piston drive : Normally we speak of Clickies and Twisties, while a Clicky has a click switch to activate it (the weakest part of the light), a Twisty has a contact in the head and teh light is activated just by tightening or loosening the head. The piston drive gives you both, the light can be activated just by tightening the head or used pushing the Piston, even in momentary mode when teh head is loose. Therefore it has a brass contact ring in the head which is a finicky system. Dirt may make the light misbehave and the necessary electronics in the light engine also may have a tendency to act strange sometimes. If teh piston is not lubed right, it may get sticky, the waterproofness of the piston is not the bes.

To cut it short : To keep this light in good working condition, you may have to clean the whole piston system and take off the brass ring eventually to clean it as well. If it works, it's a versatile light with enough brightness and a good beam.

Upon receiving it'll probably work like a charm, don't worry!

As everything with moving pieces and unsealed, it will get dirty by using it and it may end up acting strange. I don't know much lights which are completely maintenance-free, but some people are lucky and their lights always work when they should, even if they never clean it...

The cleaning process is not that complicated, besides removing the brass-ring you just use a cloth, maybe with alcohol and wipe the piston, threads and contacts off. Then slightly relube with silicone (non petroleum based) grease, if you don't care about o-rings and watertightness any other grease does it as well. Some people simply remove the o-ring from the piston, the piston then works smooth even if a little dirty, no more water protection obviously, if the light os not used in wet conditions, you don't need it.