BATTERY-CR2016

a CR2016 Lithium Coin Cell Battery. These are very common in small electronics, but it is important to understand what the numbers mean to ensure it fits your device correctly.
​Breaking Down the Code: CR2016
​The alphanumeric code on the battery isn't random; it describes the battery's physical dimensions and chemistry:
​C: Lithium chemistry (3\text{V}).
​R: Round (cylindrical/coin) shape.
​20: The diameter of the battery in millimeters (20mm).
​16: The thickness (height) of the battery in tenths of millimeters (1.6mm).