D battery

A D battery is a standardized size of a dry cell. A D cell is cylindrical with an electrical contact at each end; the positive end has a nub or bump. D cells are typically used in high current drain applications, such as in large flashlights, radio receivers and transmitters, and other devices that require an extended running time. A D cell may be either rechargeable or non-rechargeable. Its terminal voltage and capacity depend upon its cell chemistry.