i've seen those ones listed above also, but when i was looking for them, he was out of them, so that forced me to improvise, i found a dude on ebay with sets of banshee billet, compression stlye ones for like $45, i wrote him and he sold me just one for $25, i got the red center ones, but he had other colors, and they have threaded collars that tighten to compress the rubber inside around the pipe
i must say, it's been working well for over a year now
edit........here they are, the dude will sale you just one, also i had to use a piece of silicon carb adapter inside of it for the silencer end, to make it thicker for the smaller pipe.
works great