Due to batches, the original motor shaft on the Creality 3 pro printer may not fit perfectly for our dual gear. After proper installation, even if the gear on the motor shaft looks a little higher than the motor shaft, it will not come loose after being. Of course, you can replace the full-size 42mm high stepper motor if the original motor shaft is too short to install the gear. UPGRADE: Perfect replacement for 3D printers Creality -10 / -10S / -10S Pro / 3 /, etc. Aluminum alloy, high-quality dual gear extrusion, stable and. This kit does NOT include stepper motor and instruction manual, we need DIY. Support: 1.75mm filament. Some customers have encountered problems with gear wear. The solution is: Had to change the extruder's e-steps from 100 to 139 Because the filament is forced to be centered in both drive gear grooves, the idle drive gear (not attached to the motor) is placed on its shaft by the motor drive gear. So, to properly center the idle drive gear, my suggestion for setting up the unit is as follows: 1. Assemble everything but do not lock the motor drive gear on the shaft. 2. Use a pair of papers to shim the idle drive gear in the center of its mount. 3. Clamp a piece of filament in the grooves and turn the motor a few turns. This should place the motor drive gear in the correct position. 4. Lock the motor drive gear on the shaft, remove the paper washers, and you should be. Material: Aluminum alloy Color: Photo color Package contents: 1 * Dual gear extruder Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The allowed measurement error is +/- 1-3 cm.