Two AA batteries with the same appeal, the battery cover screw it. If the cover is tightened, then again a little harder TIGHTEN! Clack! Only then can the lock of the lid is snapped. Protects against unintentional opening, especially when back rules.
The control range is ok.
Battery life as normal.
Battery exchange: with battery compartment open take vibrator down in a hand, the palms of both hands beat against each other, include batteries' out. No Problem.