Bbb rollerboys sram jockey wheelsreplacement derailleur jockey wheels from bbb made from grivory composite material provided by ems swiss grivory is the proven material for metal replacement features composite material provided by ems swiss with 40 glass fiber mixture complete set of bushings for different shifting systems included equipped with special internal lubricant systemspecifications11t compatible with the following sram systems sram 90sl 20012002 90 2003 sram x7 2