Item Type: POM Pulley Wheel Set_x000D_ Product Material: Accurate steel, rubber_x000D_ Pulley Inner Diameter: 5mm / 0.2in_x000D_ Pulley Bearing Outer Diameter: Approx. 8mm / 0.31in_x000D_ Pulley Height: Approx. 9mm / 0.35in_x000D_ Chute: Approx. 6mm / 0.24in_x000D_ Pulley Outer Diameter: Approx. 15mm / 0.59in_x000D_ Eccentric Spacer and Round Column Inner Diameter: Approx. 5mm / 0.2in_x000D_ Eccentric Spacer and Round Column Height: Approx. 8mm / 0.31in_x000D_ Product Use: For 3D printers 1A TOTAL OF 48PCS: Including 16Pcs POM wheel, 16Pcs round column, 16Pcs eccentric spacer. Wonderful 3D printing accessories set for you 2SMOOTH WITH LOW FRICTION: POM pulleys are strictly designed and tested to make them work smoothly and stably; silent design, low friction, and bearings are durable. Getting POM wheel will make your work even better 3APPLICABLE MODELS: Provides good performance for all DIY 3D printers, such as for Creality CR10, for Ender 3, for Ender 5, for Anet A8, for E10, for Anycubic, for Anet series 3D printers, for Tevo Tarantula, CNC Router Hybrid, 8020 3030, etc. 4NOT EASY TO RUST: Possess better performance than iron bearing wheels. The 3D printed wheel with rubber bearing is new development. Good surface without rust 5HIGH ACCURACY AND FAST SPEED: These 3D printer wheels move smoothly, with low noise and high printing accuracy, which can improve the printing speed well 16 x POM Wheel 16 x Eccentric Spacer 16 x Round Column Note that there is a movable copper ring between the bearings. Ring movement is normal, otherwise the bearing cannot turn. It's not a quality issue.