This upgrade kit is special designed for Ender 3/3Pro 3D printer, introduces support for three-point leveling. This Upgrade Kit Including XY Axis belt Screws and Aluminum Plates Kit Perfect flatness and beauty of the surface, rigid surface for balance heating bed. Made of aluminum alloy, brushed and anodized for perfect flatness and beauty, the rigid surface is used for the balanced heating bed Meet the quality standards, tested before shipment, you will gain maximum accuracy, efficiency, and high print quality. Specification: Item Type: 3D Printer Parts Material: Aluminum alloy Color: blue Size:35.4 x 9.5x 7cm/13.9 x 3.7 x 2.8 inch Package Includes: 1Set Aluminum Plates 1Set Screws Kit 1x X Axis Belt 1x Y Axis Belt 1x Linear Rail : 1.Please allow 1~3 cm error due to manual measurement, thanks. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Please understand, thank you.