... carbon steel is zinc RKM/GCS Conveyor Ball Transfer Unit/ conveyor ball/ ball conveyor in tower shape or disc shape ... Dia50 carbon steel,stainless steel,nylon1. Conveyor Ball Transfer Unit/ conveyor ball/ ball transfer unit is often used in light-duty industries ... conveyor chain, conveyor wheel, conveyor bearing, wheel chain, ball transfer unit, return bracket, press bearing, skate wheel, plastic ...