Ive used a peep without a tube for the last few years and just today had a new peep put on with a rubber tube. Im not a real big fan of the tubes because of the fact that they wear out quick and could snap. The only reason i went back to one is because i got tired of turning my peep everytime i knocked an arrow so that i could see through it at full draw. I have a zebra zs twist string but it still has some twist. At least with the tube sight i know when i draw it will be where it needs to be. But i prefer the ones without the big chunk of rubber.