N battery

Mercury batteries of the same dimensions are no longer manufactured because of their toxicity.

Former mercury cells, such as the Mallory RM401, Duracell RM-401, IEC-MR1, etc., were supplanted by the alkaline Kodak KN.

Rechargeable N-Series batteries may be charged in an AA charger using a makeshift adapter (such as a small metal slug or a spring).

Common uses for this size of battery include some small flashlights, radio pocket pager receivers, remote control door chimes, glucose meters, small desk clocks, wireless microphones, laser pointers, some vintage calculators, some slot cars, film cameras, and small vibrators.

However, as technology has improved, many of these devices now run on button batteries.