DescriptionMade of material, these wheels are durable and sturdy. There are total 10 pieces of wheels in one set, which you may use for many projects. They are normally used for 3D printers, CNC machines and many other machines, lightweight design, exquisite appearance, and easy to use.Features- Color: Black. - Material: Plastic. - Size: 2.40 x 2.40 x 1.02cm/ 0.94 x 0.94 x 0.40 inch. - The plastic roller bearing is a passive round model pulley to V-slot for 3D printer. - This v-slot model is widely used for wheel alignment, wire and belt. - The outside of the wheel is made of material with good physical, mechanical and chemical properties. - This roller has an outer diameter of 25 mm, a thickness of 11 mm and a bore of 5 mm. - These pulley bearings have motor ball bearings, resistant to rust, wear, excellent rub resistance and work smoothly.