Deep groove ball bearings, fashionable, slide flexible. The product is outer ring with U-shaped groove pulley bearings,compression wear. Each can load 79kg,good to use and long service life. Suitable for furniture hardware accessories,Doors and windows pulley. Weight: 41g/pc colour:Orange Material:Plastic + bearing steel Size:0.6 x 3 x 1.3cm/0.24 x 1.18 x 0.51 inch(ID x OD x T) Inside Diameter: 6MM Outside diameter: 30MM Thickness: 13MM Package Contents: 16 x Bearing Pulley Wheel Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.