The supplied battery will last at least 2 seasons, and can be easily replaced for under $6. Not the little wafer type watch batteries that go dead in a week. And is powered by a 3 volt lithium camera battery. This GREEN LASER has the maximum wattage allowed by law. I am the ONLY supplier of this Quality unit. They WILL NOT HOLD UP and you will be very disapointed. Don't be fooled by the cheap Chinese imitation units flooding the market. That we have patented the mount and the use of the stabilizer threaded hole for mounting sights onto a bow! This is the only laser sight company in the world authorized to use a mount that uses the stabilizer threaded hole to mount the laser unit. This is not a cheap little laser pointer.this is the only unit that mounts on your bow by using the stabilizer hole in your is so unique. Quality product at a very reasonable price. This unit was designed by a serious Engineer/Bowhunting Instructor who got tired of pin type sights and peep sights and saw the need for a high tech. more quality, MILITARY GRADE BRIGHT GREEN laser sight available for a bow on the market today. Affordable, easily adjustable, professional. Bowfishermen and 3D shooters.this is by far the most compact. On sale now through March 15th! Bowhunters.