Various series are available for fob batteries, but the CR2032 battery is the most commonly used one. The batteries are different in size and capacity. There are some similarities that may be there with diameter, voltage, chemical composition, discharge current rate, and manufacturer. To check the technical data of batteries To check the battery sizes For example, CR2032 battery, in this, the C specified Lithium chemical composition, the R indicated the shape of a Round, and 2032 indicates 20mm wide size and 3.2mm tall. Similar coin cell batteries list CR1220 CR1616 CR1620 CR1632 CR2016 CR2025 CR2032 CR2412 CR2450