Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Save your money.

SSI Sight-Rite Bullet Laser Bore Sighter .222, .223There is no on/off switch, it just works by tightening a reverse-threaded plastic screw on the end where the primer would be. After fiddling with that for a few minutes, you better work fast once you turn it on. The batteries are good for about 10 minutes, and then they die. Of course, then there's the problem I had where the bolt accidentally closed on it and the thing was lodged in my chamber and wouldn't come out until I used a mallet and dowel rod to pound it out... I do NOT recommend this product to anyone. Buy the kind of laser that goes in the muzzle, not in the chamber.