Sony 3V lithium watch battery, all types (from CR1220 to CR2450)
Amazon.com: Eventronic Watch Battery Replacement Tool Kit,Watch Back Remover Tool,Watch Case Opener Tool,Watch Tools Case Back Opener,Watch Repair Kit,Watch Case Opening Pry,Spring bar,Tweezers,with Carry Case : Clothing, Shoes & Jewelry
Amazon.com: #394 Renata Watch Battery : Health & Household
Help on Replacing your Watch Battery from WatchBattery (UK) Ltd