Fenix ARB-L18-3500 is a Premium Quality High Capacity 18650, 3500mAh Lithium - ion battery specifically designed for high intensity flashlight use and is the perfect companion for all current Fenix 18650 powered lights.

ARB-L18-3500U battery features:

High capacity (3500mAh), great reliability and compact design
Triple overheat protection including relief vents for safety and reliability
Built-in over charge, over discharge and short circuit protection
Impact resistant structure
Protruding positive contact allows use in series

Dimensions
Diameter: 18.6mm
Length: 70mm

Please check your application as the slightly increased length and diameter of these batteries means that they may not fit some older products.