I had a Tasco on a .22 cal for THIRTY YEARS before it went bad. It got too cloudy to see through. Tasco's bite so bad I replaced it with another Tasco. $10.00 for the first one and $15.00 for the one I replaced it with this year. I have Tasco's on most of my rifles and that's the only one I ever had a problem with. I think I'll take them all off and replace them with TASCO'S. They stink.