The idea of using idler pully for 3D printer is providing supported passive movement for x-axis and y-axis timing belt. Idler pully makes the 3D printing stable and move smoothly. 6mm width idler pully is designed for 6mm width timing belt, which is quite common width for x-axis and y-axis of most 3D printer. Do not put 10mm width idler on if you are using only 6mm width as you will not have stable printing.
The idler pulley we have in stock including