This is a really versitile torch set up and brilliant for camping, nature viewing or for just looking for lost items in the garage, this head torch leaves your hands free and if that weren't enough, has an on/off sensor, which means with just a wave of the hand in front of the lamp, the light will magically come on. The elastic that the torch is attached too, is stretchy and big enough to put over a helmet if required and the power for the torch is from 3 AA batteries which fit into the battery box on the back of the unit, which balances out the torch on the front The lifetime of the bright Cree© LED light is approximately 100,000, so plenty of use for keen cavers and as it is compact, perfect for confined spaces. Weighing only 125grams, (without battery) you won't notice you are wearing it and the shock and weatherproof housing is made from aircraft aluminium, so will take quite a bit of abuse. It has a variable light out put from 100% to 25%, reading light and flashing SOS mode. and is supplied with 3 AA batteries, which fit in the battery housing at the back of the head strap.