use the rubber to hook to your peep. i tried to use one that doesnt use a rrubber and the pro shop guy said you have to mess around to get it to line up i didnt really want to have a nice buck come by andits out of line!!!!!!! i know people will say that rubber will come off but if you replace it often it will only come off every 1000 or so shots.i have used one for many many years now and it hasnt let me down yet!!!!!but who knows!!