I have a 4X clear lens by High Tech Archery Optics. AKA archeryoptics on the forums. The lens is in great shape and was barely used. It's center drilled for .019" fiber. Great lens, but I've decided to use my 6X lens instead. Fits the Viper scope and any other housing requiring a 1-3/4" diameter lens. They run about $70 new, but you can have this one for the low, low price of $50 tyd.