I have a 3-10x40 scope on my longbow. I can flip a button and it has two additional features: a lighted reticle and night vision capability. It's wonderful except for two things: 1) my longbow, bow quiver and three arrows weighs about 33 ounces, the scope weighs about three pounds! 2) at night, it's really hard to follow the flight of the arrow though the scope, so I think I will get the knocks that glow when the arrow is shot. Mounting the scope isn't too hard unless you put it on a really expensive custom long bow. I just drill holes in the riser, mount a Weaver rail and use Weaver scope rings. If I put it on a really expensive bow, I just use duct tape.