This is a 1930's mining lamp consisting of a battery enclosed steel case and a small lamp worn on the miner's cloth cap. It had 6 candlepower and could operate for about 12 hours. That is actually impressive considering a 4 D-cell "Mag Light" has around 11. My inspection headlamp, on the other hand, has around 72, and, on an equivalent low setting, could run for a few days.