The MuRata 370 is a silver oxide button cell with high performance for compact electronic devices. This long lasting and reliable cell features 1.55 volt power and a capacity of 40mAh that beats out competing batteries when it comes to run time. As a watch battery the MuRata 370 is peerless, offering long lasting life for similar low drain devices. On top of that, silver oxide chemistry is safe, reliable and mercury free.