Feyachi 9mm Red Laser Zeroing Bore Sight is fast easy to use bore sight that can help you save time and money on cartridges and shells. This is a class IIIA with less then 5mW power output and 632-650nm red laser wavelength. The sighting range goes from 15 to 100 yards. The dot size at 100 yards is approximately 2 inches. The best temperature for operating this bore sight ranges from 14 degrees F or 122 degrees C to -10 degrees F or 50 degrees C. This Feyachi 9mm Red Laser Zeroing Bore Sight is a light compact durable brass construction that will sit perfectly in any 12 gauge or 9mm Luger chamber. Feyachi 9mm Red Laser Zeroing Bore Sight is caliber specific. There are 3 sets of batteries that are included with purchase (6 total), each of these sets will last up to an hour of use. The batteries are wrapped in a clear plastic please remove before use and also remove the batteries after use.