from LaserLyte's website FAQs on LT1:Now, I'm not saying you're wrong. I'm just sort of interested in the LaserLyte training system... Though I am experiencing a long wait for an aswer to an email question to them... So I thought I'd look up your problem... sorry this is taking so long to fix.. please let us know the outcome.A: For training mode, the LT-1 uses 3 batteries size 399 or SR927W. For constant on mode, the LT-1 uses 3 batteries size A76 or G13.