Great way to keep a spare battery for an Aimpoint T1 or a Leupold Mark 4 (illuminated reticle model) close at hand. Low profile design with a tethered and 'o-ringed' battery cap.
Pros: Low profile and light weight
Cons: Takes up 1 1/2" of rail space.
This review was written in the old system and had content requirements that are different than reviews written today.