I bought one of those sight tools and it is nicely made. I also bought the Tech Sights Rear Aperture Sight for my SKS and a thinnner front post- What a waste of money! What they don't tell you in the add is that the sight must come off to remove the receiver cover, in other words, every time you have to clean the rifle - and no, it DOES NOT return to zero! Also the receiver cover retaining pin must be replaced with a threaded bolt (supplied). Problem is, on the Mod.59/66 SKS you cannot remove the original retaining pin without either grinding off the little tit on the pin (which prevents it from being withdrawn completely), or you must drill a smaller hole in the receiver next to the retaining pin hole for the tit to pass through. Either way, it's not a good design, and certainly isn't worth the money.