I had a friend hunting with me down in Missouri once. He stalk up within 30 yards of about 40 turkey drawed his bow back and the rubber on his peep snapped him on the forehead. Needles to say he couldn't see through his peep, but he shot any way and missed all 40 of them. He has never use the rubber band peep again. Once I was at a 3D shoot and a friend rubber broke. He could see through the peep so he keep shooting. His 30 yard pin was about 6 inch high and 40 was higher. I told him that there would be a big difference. He went home and into his pro shop Shot in over a chronograph than put a new rubber on. He lost 15 fps with the rubber. He got on the phone right away and called me to tell me that I was right about the rubber and how it sucked. Now he doesn't use one any more. I never like them because they always brake at a bad time for me and some time shade the peep hole if the light is just right. To each there own if you like them than use one. I'm just talking about some of the things I have seen happen with them.