All Balls offers a complete line of OE replacement and universal chain rollers along with a complete application guide. The universal 34mm and 38mm Polyurethane chain rollers have a 98A Durometer hardness for long life and feature sealed precision bearings with two additional outer seals to prevent water and dirt from contaminating the bearings. They are the longest lasting chain roller in the industry. The OE replacement chain rollers that mount directly to a frame boss are made from hi-performance self lubricating nylon.Quality design and construction of every All Balls piece meets the toughest standards and conditions - from daily commuting to full-on racing, all older bearing and seal designs are upgraded to the best and latest specs and designs.