Feature: 1. 48PCS: The set includes 16PCS POM wheels, 16PCS spacer columns, and 16PCS hexagonal eccentric spacers, which is a very complete set of 3D printing accessories. 2. GOOD STABILITY: Our pulleys are strictly designed and tested to make them work smoothly and stably; silent design, low friction, and durable bearings. 3. WIDE APPLICATION: This 3D printer pulley can basically adapt to most 3D printers on the market, so you can use it with confidence. 4. STAINLESS: This 3D printing wheel is different from the previous iron bearing 3D printer pulley, it is less prone to rust and has a longer service life. 5. GOOD HELPER: This 3D printing wheel of ours has high printing accuracy, which can improve the printing speed very well and make your work more perfect. Specification: Item Type: 3D Printer Pulley Wheel Set Material: Precise steel and POM Inner Diameter of Pulley: Approx. 5mm / 0.2in Pulley Height: Approx. 10mm / 0.39in Chute: Approx. 6mm / 0.24in Outer Diameter of Pulley: Approx. 24mm / 0.94in Eccentric Spacer and Cylinder Inner Diameter: Approx. 5mm / 0.2in Eccentric Spacer and Cylinder Height: Approx. 6mm / 0.24in Product use: For 3D printers. Package List: 16 x 3D Printer Pulley Wheel16 x Eccentric Spacer16 x Round Column Note: Note that there is a movable copper ring between the bearings. Ring movement is normal, otherwise the bearing cannot rotate. It's not a quality problem