Description:This boresighter is designed for observation in your shotguns without shooting. Simply install the included batteries, place the entire assembly in the chamber and gently close the action. The reticle emits a simple red laser beam, providing a precise reference for zeroing in the reticles or ranges. Features:Fits 12 Gauge shotgun chambersLightweight and durableGuns with any sights (iron, optical, laser, holographic, etc.)Long Viewing RangeSpecifications:Max. Output Power: Less than 5mWMaterial: BrassLaser Wavelength: 635-655nmObservation Range: 15 to 100 yardsDot Size: 1.5" 100 YardsLaser Beam: lt; 5mW Sheet: Red Power Source: 3 x LR44 Button Batteries (Not Included) Quantity: 1 PcNote: Please allow 1-3mm error due to manual measurement. Pls make sure you do not mind before you make a bid, due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!No Retail Package Package Included:1 x Laser 12 Gauge Boresighter1 x User Manual