This sight-rite muzzle laser bore sighter is a versatile system that works with all calibers from.17 to.50.It features a unique adaptor kit which provides stable alignment, producing accurate bore sighting results.The dual o-ring system will not damage the barrel end and there is no metal to metal contact.A protective tube and batteries are included.Type: Laser BoresighterCaliber: 50 CalStyle: LaserMaterial: MetalQuantity: 1Battery: LR44Mount: Muzzle