Other than MBWs, most rep cases are not manufactured to the same dimensions as gen cases & rep crystals tend to be made of lighter gauge (thinner walled) material. The inside dimension of gen xtals, because of their thicker sidewalls, is usually too small to fit over the flange opening on rep cases. Your options are to either use 1 of the better aftermarket xtals (search ebay for Clarks), grind down the outer perimeter of the flange opening or grind down the inner circumference of the crystal. Keep in mind, too, that the crystal needs to fit snugly over the flange to help (along with a crystal ring) maintain a watertight seal.