ATOPLEE 4pcs Round Groove Nylon Pulley Wheels Roller Bearing for Slide Gate/Angle Bar/Drawers, 8x32.5x10mm Injection Material:White POM Bearing Material:High Carbon Steel Model:HU-0832.5-10 U groove size (Width*Depth): 5mm*3.8mm Product size (Internal diameter *External Diameter*Thickness):8mm*32.5mm*10mm