GSM Outdoors .22 Caliber Bullet Laser Bore Sighting System Get meticulous accuracy with the most exacting tolerance specifications in the sighting industry. From the very smallest to the largest 12 gauge casing, our precision machined caliber specific sighters deliver unparalleled results every single time. Features: - Precision machined brass casing for optimum accuracy - Caliber specific factory alignment - High output laser - Units include (3) three Alkaline button cell batteries (varies by caliber)