TACFUN Bow Arrow and Crossbow Archery Red Laser Sight sighting Tool Boresight bore sight Minimum Range for Sighting: 15 yds Maximum Range for Sighting: 100 yds Class IIIa 635nM Less Than 5mW, Avoid Direct Eye Exposure to Beam. Operation: On/Off End Cap Battery Life: ~ 20 min ( COME WITH BATTERIES) Laser Type:Visible Red Laser Power: &lt; 5mW Construction: Brass