Review on BCZAMD Upgraded 3D Printer Parts: Adjustable Y-axis Synchronous Belt Stretch and Straighten Tensioner for Ender 3 Pro 3D Printer by Nico Ramdeen

Unit is well built but uses a gear instead of a smooth idler. Since the stepper motor already has a gear, the belt cannot always fit exactly between the teeth of both gears. If you move the bed back and forth on the Y axis, you can hear and feel it. The bed doesn't turn. My solution was to remove the stock idler and install it in place of the gear. Since the smooth wheel is a bit wider, the small nylon spacers had to be sanded down a bit to make them fit. Very easy to do. A few strokes on a flat piece of 220 grit sandpaper will do the trick. The bed runs fine now. I am happy with the purchase