Solomone Cavalli Vector Optics 0.223 REM 5.56 mm Caliber Cartridge Laser Bore Sight 4/15, Red Maximum output power: &lt; 5 mw, wavelength: 635-655 nm, power source: Three (3) LR41 button cell batteries or equivalent This arrow laser sighting tool is designed for all standard thread arrows Precision sighting & zeroing tool, accurate, heavy duty & dependable, saves time & ammo Caution: Be sure not to release the arrow and ensure it is pointed in a safe direction before attempting to sight your bow or crossbow