A hand holdable light comprises: a light body having a forward portion, a rearward portion, and a central portion between the forward portion and to the rearward portion; a light source proximate a forward end; and a switch for energizing the light source. The rearward portion has a non-circular cross-section; the switch is on the forward portion; and the central portion has a recess opposite the switch. The light is holdable by a hand with a finger or thumb proximate the recess and the other of a finger or thumb proximate the switch. A battery assembly comprises: a battery housing for receiving and connecting a battery; an electrical switch on a first end of the battery housing; and a pattern of electrical contacts on a second end of the battery housing, wherein ones of the electrical contacts are connected to the battery.