The Advanced Combat Optical Gunsights (ACOGs) are internally adjustable, compact telescopic sights with tritium illuminated reticle patterns for use in low light or at night. Bindon Aiming Concept (BAC) models feature bright daytime reticles using fiber optics, which collect ambient light. The ACOGs combine traditional, precise distance marksmanship with close-in aiming speed. Designed for use with the MSR family, every feature of the mechanical and optical design was chosen for a single purpose: to provide increased hit potential in all lighting conditions, without failure-prone batteries. Covered under a limited lifetime warranty.