PACKAGE INCLUDED:2 Pack of 2500mAh 18650 Lithium-ion rechargeable batteries HIGH QUALITY: Enjoy a long storage life, no memory effect, high energy density, and a portable light weight . HIGH PERFORMANCE:Automatically protects against overcharge, over discharge and short-circuiting. LENGTH: 2.55 inches (65 mm),DIAMETER: 0.71 inches(18 mm)