This self-contained battery tester is also a battery holder AND a key chain. Carry in pocket or purse to test if your battery is weak, dead, or at full power.

Features

• Self-contained battery tester
• Convenient for pocket or purse
• Tests sizes 13, 312 and 675 (NOT compatible with size 10) 
• Red light emitted to show battery life 
• Storage compartment for 2 extra batteries 
• Quick and easy to use