... your choice, also called ball bearing cage,ball bearing bushing ,& ball bearing bush,ball retainer & Die parts ... glossiness,buildiness,abrasion resistance,long service-life. The bushing has 3 types,which is made of steel ... like ceramic,plastic etc.)NO 1: Plastic bushing (blue,white colour,POMS,POMBS,POMM,POMBM,POMT ... ,POMBT type;NO 2:Aluminum bushing(white,cupreous colour,ALBS,ALS,ALBM,ALM, ...