Hi Glad you like it mate ,its a awesome little unit.
Don't forget that you can put the 50mm head onto the pistol to make the focused beam wider & make it even smaller/lighter if required.
Ref putting the battery cap on
Hold the cap in your left hand with the contacts facing down & screw the main body UP into the cap making sure its lined up.
I find it very easy doing it this way although I do get a bit of practice as I test every unit prior to dispatch.
Kind regards Andy