... 300,000pcs (1) Housing Materials: steel, aluminum alloy, zinc alloy. wheel material: PP, steel(2) surface: anodizing, zinc plated(3) it ... be supplied by us. offer OEM service,sliding window roller(door roller, pulley for door and window,window roller,aluminum housing window roller,nonstandard window roller) sliding window roller(window roller,aluminum housing window roller,door roller)