AG1 LR621/364 1.55V/2-10Pcs Alkaline Button Coin Cells Watch Battery Batteries are single use batteries designed for various consumer electronics. Originating from Mainland China, these Yuform brand batteries have a nominal voltage of 3V and a nominal capacity of 13mAh. The LR621 size and Zn/MnO2 chemical composition make them suitable for a range of devices, certified with CE for quality assurance. Perfect for powering watches and other small gadgets, these button batteries come in a pack of 2 to 10 pieces.