# Button cell |  | A **Button cell**, watch battery, or coin battery is a small single-cell battery shaped as a squat cylinder typically 5 to 25 mm in diameter and 1 to 6 mm high – resembling a button. Stainless steel usually forms the bottom body and positive terminal of the cell; insulated from it, the metallic top cap forms the negative terminal. | |-|-| | | wikipedia:: [Button cell](https://en.wikipedia.org/wiki/Button_cell) |