Product Description 4040 aluminum profile Y-axis synchronous belt stretching fit for for Creality Ender3 Pro/Ender3 V2/CR-20 Pro 3D printer. Note: Not fit for Ender 3, Ender 3X, Ender 5 Match with 6mm belt, upgrade the tension tensioner to adjust the belt freedom, much better than original 【Material】Material: aluminum alloy; Surface Treatment: anodizing 【Install】Already assembled,you don't need to assemble it by yourself Package Include: 1 Kit Y-axis Synchronous Belt Stretch Straighten Tensioner 4 x M5 T Nuts 4 x M5x8mm screws