Casio B650W Mens 50m Black Silver Digital Alarm Chrono Quartz Watch~New Battery | eBay
Casio Watch A158W Model 593 Silver Digital Alarm Chrono Original NEW BATTERY | eBay
Amazon.com: Casio Illuminator 10-Year Battery 100M Water Resistant LED Backlight 5-Alarm Chronograph Digital Stop Watch AE1500WH-2AV : Clothing, Shoes & Jewelry
My brother's watch lasted a decade on the original battery, and these batteries are tiny, so I'm just wondering.... how long with a big enough battery could one last? : r/casio