Features: Experience superior Precisions with Kobra3 Gear Set, featuring integrated shafts that ensures concentricity and reduces eccentric rotation for smoother transmission. from high reduction ratio, these gears offer enhanceds extrusion torque treated with nanocoating for exceptional strength and durability. for 3D printing enthusiasts and professional high performances components to enhances their printing efficiency and quality. Perfect for use in various 3D printing applications, these gears provide performances in both home and professional, ensuring consistent and precise. The gear improves meshing performances and load capacity, while construction minimizes materials usage without compromising strength, making it for advanceds 3D printer parts. Specifications: Materials: ABS Diameter: 21mm/0.827inch Package Includes: 1Set Extruder Gear note: Please allow 1-3cm error due to manual measurement. make sure you not mind before bid. Due to the differences between different monitors, the picture may not reflect the actual of the item.