Specification <br> Length: 44.5mm; Tail width: 9.5mm; Head width: 6.3mm <br> Laser Wave length (nm:) 640 to 660<br> LED Type: visible red laser<br> Power: <5 mW <br> Construction: Brass<br> Sighting Range: 15 to 100 yards <br> Dot Size: 2 inches at 100 yards<br> Temperature: -10℃ to 40℃<br> Operation: On/Off End Cap <br> Battery Type:6 X AG3 (Included)<br><br> How to use the bore sight? <br> 1.Unscrew the back cap from the bore sight by turning counter clockwise<br> 2.Stand the bore sight on a flat surface with the laser side pointing down<br> 3.Insert batteries (+ side up) inside the rear opening<br> 4.Carefully push down and turn the screw cap clockwise to tighten the cap (the laser is now on)<br> 5.Place in your rifle’s chamber and close the bolt<br> 6.To remove - open the bolt if it does not automatically extract, manually remove the unit by tilting the rifle’s barrel upward (always practicing safe firearm practices)<br> 7.Unscrew the back and remove the batteries to turn the unit off <br> Package included 1 X Bore Sight 6 X AG3/LR41 Batteries