3Dman GT2 20 Toothless Bore 5mm Aluminum Timing Belt Idler Pulley for 6mm Width 3D Printers (10pcs)

Worked very well on my printer

A well-made product. Timely delivery (overnight than the expected time). Packaged well. Will recommend.

These work like they're supposed to. Thumbs up

They arrived in good shape and work for an Ender3 belted Z axis upgrade.

This is a good set of pulleys that is very useful for a quick gear change ratio. I use them for getting a bit more resolution on telescope focusers controlled via stepper motors. They are true to size and can be bored out a bit larger if necessary depending upon your shaft OD. The included belt is fiber-based and flexible, not the steel core type that is prone to failure.

They all have 5mm Bore and bearing is almost flush with the body -- so you need speacial shim/washer -- 6mm OD max .. where do you get that! These vendors keep selling these but there is attempt to make them easy to use -- I use them as idlers and you can't really tighten the core too much .. no matter what washer you use - they work but are very uselessly designed.

Great price on pulleys that are useful in Middle and High School science projects. These can be used with string or twine instead of a toothed belt.

Exactly the right size for the Y axis motor on my Ender 3 Pro as my replacement motor did not have a gear attached to it