D8 Red Laser Bore Sighter 300 Win MAG Cartridge Sight Boresighter 300win Hunting (Brass) Minimum Range for Sighting: 15 yds Maximum Range for Sighting: 100 yds Wavelength: 645nm, 632nm Operation: On/Off End Cap Laser Type:Visible Red Laser Power: &lt; 5mW Battery: LR936 X 3 (battery included)