... ,POM; *Size:Customized; *low friction coefficient ball cage in quality linear ball cages in different types and ... specifications for your choice, also called ball bearing cage,ball bearing bushing ,& ball bearing bush,ball retainer ... made of other material ,just like ceramic,plastic etc.)NO 1: Plastic bushing (blue,white colour,POMS,POMBS, ... to give you the best service. plastic Ball cage from China