... threaded, male threaded & spring loaded axles. Product DescriptionGravity Roller, use precision bearing, stable turning, suit for most ... , Nylone 66 Cover material: PP 6002 double face sealed precision bearing GB/T276-94 Stainless steel ... 12mm Surface treatment: noneExtensive use transporting roller, roller, gravity roller, conveyor roller Stainless Steel gravity roller with plastic bearing housing