20 Gauge Laser Cartridge Bore Sighter 20 Gauge Laser Bore Sight Shotgun20 Gauge Laser Cartridge Bore Sighter 20GA Shot Gun BoresighterMaterial: High Quality AluminumColor: RedWave Length: 635-655nmBattery: 3x AG13 Button cell batteries(or equivalent)(Included )Battery Life: 1 hour maximumRange for Sighting: 15-100 yardsBest Range for Sighting: 20-30 yardsOperation: On/Off End CapConstruction: BrassPower: Less than 5mW