I had about a 25$ one about 5 or 6 years ago, I only used it for a month or two. I didn't really find an advantage of it over the iron sights. It's supposed to make it easier to shoulder and aim the weapon more quickly, which it did, but if you're decent with iron sights it's not really that advantageous. What would you use it for? You might be better off just getting an air rifle scope, or sticking with iron sights.