The Extended Runtime Kit from Fenix comes with a modular extension tube and a battery holder for four 18650 li-ion batteries. It is compatible with TK75 flashlights. Multiple extension modules can be attached to provide additional runtime. The battery module will extend both the runtime and the flashlight housing. The included 18650 lithium-ion battery holder also features protection against over-charging, over-discharging, and over-heating.

Specifications:

Dimensions: 4.5" x 1.1"
Weight: 2.2 oz