Energizer silver oxide button cells energizer 635318 the energizer sr731 329 is a silver oxide button cell battery with zero mercury it has an average output capacity of 39mah the battery will reliably power your watches toys and calculatorsthis silver oxide battery can be used as a replacement for the following batteries rw300 24 525 gs18 and s42 energizer 635318 size sr731 silver oxide button cell