Maxell 348 SR421SW 1 Battery

Do not use (inherently low performing) alkaline batteries in place of silver oxide in any timepiece: they have declining power output.

Made in Japan
Genuine Maxell Hologram Anti-Counterfeit Packaging (other package is not genuine)
1.55 volts 12 mAh
Mercury Free
This is a primary non rechargeable disposable battery

The 348 is a long life silver oxide chemistry with non-declining power output; alkaline batteries of the same 1.5 voltage start at 1.5 and at the half life are at .8 volts, silver oxide start at 1.55 volts and maintain the voltage until expiring. This is why silver oxide batteries are always used in watches, insulin pumps and sniper scopes or mission critical situations. Never use alkaline batteries for any device requiring a steady constant voltage. A watch with declining voltage may not be reliable.

Fits and Replaces: This is from the American Watchmakers-Clockmakers Institute 2008 Edition Handbook "Battery Number System". This Battery is cross-referenced as: AWCI S72, Energizer 348, UCAR 348, Union Carbide 348, Eveready 348, Interstate Batteries AWAC5090, Maxell SR421SW, Panasonic SR421SW, National SR421SW, Seiko SR421SW, Seiko SB-A6, Toshiba SR421SW 

Fits and Replaces:

• AWCI S72
  
• Citizen 280-77
• Energizer 348
• Eveready 348
• Interstate Batteries AWAC5090
• Maxell SR421SW
• National SR421SW
• Panasonic SR421SW
• Pulsar WAC5090
• Pulsar Y151
• Pulsar Y151A
• Seiko 1F21
• Seiko 2J30
• Seiko 2J31
• Seiko 2J41
• Seiko 2J80M
• Seiko SBA6
• Seiko SB-A6
• Seiko SR421SW 
• Seiko Y151
• Seiko Y151A
• Sportline Pedometer 4144
• Timex M Type
• Toshiba SR421SW
• UCAR 348
• Union Carbide 348
• Varta 348
• Varta V348
• Vinnic 348
• Whittnauer Ladies Astor Model 11P06