If you have our TRU-Lite(TG55) or TRU-Lite Xtreme(TG56) sight light that uses a twist on/off motion to operate, it takes: (3) ENERGIZER 392, 384 or 192 batteries. If there is a height problem, (too low) a #8 lock washer can be installed at the LED end of the light, then place the batteries on top and secure. You can purchase batteries for your TRU-Lite and TRU-Lite Xtreme light on our website, TRUGLO part # TG988A
Our new TRU-Lite Pro(TG57) sight light operates on a single CR927 battery that is installed via a tray inside the light. There are small markings inside the sight light which indicate which direction the "+" and "-" sides on the battery face. You can also purchase these batteries on our wesbite, TRUGLO Part # TG988G.
The batteries for the twist on/off style lights will install with their positive (+ side/smooth side) facing outwards, away from the illuminated end of the light. If there are any questions regarding battery installation feel free to give our Customer Service Department a call for further information and help.