The Rubber O-Ring is used as a dust seal on our original 4 pawl drivers. If your hub is missing this piece, dirt, dust, mud and debris could potentially enter the drive mechanism of your hub. This is not a great thing. So now you can purchase a replacement.
There are two different seals used in Profile Racing’s cassette hub drivers:
Mini Seal– Used on Mini BMX, Totem BMX, High Flange BMX, & Classic MTB style(4 pawl) Cassette Drivers. It is a standard rubber o-ring.
Elite Seal- Used on Elite BMX & Elite MTB style(6 pawl) Cassette Drivers. It is made of black Nylon and marked “Profile Racing Made in USA”.