40s＆w Green Dot Laser Boresight With 3 Sets Of Batteries (Packaging Six) 

• Class IIIA laser, less than 5mW, safe and harmless. Caution: Keep the green laser beam away from eyes.
• Faster gun zeroing,high accuracy,reduce cartridges and shells wasted.Made to fit the 40s＆w chamber, caliber specific.
• Comes with 2 sets updated batteries which can last three hours.Each set of battery can last up to 1 hour.Easy to sit perfectly in the bore,sturdy brass construction,the boresighter is high quality.Before use it, remove the plastic packaging of the batteries.
• The bore sight has clear and bright green laser, which can provide longer distance sighting than red laser bore sight, work well in any weather conditions.
• By projecting a straight green laser beam from the center , providing a precise reference for zeroing in on your target, allows for quick and accurate resetting of any sights.