Features: This is a durable drive parts used for MK7/ MK8 extruder, suitable for most 3D Printers. High bearing capacity, ensure your printer working smoothly. Made of high quality brass, no rust, and no corrosion, durable to use. Light and portable, easy to install. 10pcs a pack, high strength and high precision. Specifications: Color: Gold Material: Brass Teeth: 26 Teeth/ 40 Teeth (Optional) Outer Diameter: Approx. 11mm/ 0.43in Inner Diameter: Approx. 5mm/ 0.2in Size: Approx. 11 x 11 x 11mm/ 0.43 x 0.43 x 0.43in Package List: 10 x MK8 Extruder Gear (Only gear, other items on the pictures is NOT included.) Note: Please allow 0-2mm error due to manual measurement. Thanks to your understanding. .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; } 1This is a durable drive parts used for MK7/ MK8 extruder, suitable for most 3D Printers. 2High bearing capacity, ensure your printer working smoothly. 3Made of high quality brass, no rust, and no corrosion, durable to use. 4Light and portable, easy to install. 510pcs a pack, high strength and high precision.