Coin cells, which are also called button cells, are small, round batteries that are commonly used in watches, toys, or keyless entry devices for cars. These Maxell coin cells have a silver oxide chemistry, and are mercury-free. This listing is for the Maxell 301 coin cell battery. The voltage of the Maxell 301 is 1.55V, and its capacity is 110mAh. The discharge current is 100mA. With the Maxell 301 coin cell, you get a flat discharge rate, which means that the voltage remains constant until the battery discharges itself.