Befenybay 2PCS 5mm to 8mm Aluminium Plum Flexible Shaft Coupling D20 L25 Connector Flexible Coupler for 3D Printer CNC Machine and Servo Stepped Motor（5x8mm）

Printer moves much smoother now after this upgrade, fits perfect with my ender 3, excellent quality

These have absolutely no pulling power, the plastic slides right out whether vertical or horizontal. Your z shaft must be secured on the end. They look cool though.

They would not clamp to the stepper motor shafts of my sidewinder X1 no matter how much I tightened the bolts.

One of them was straight but the other was completely out of round. These were purchased for the Z axis on my 3D printer and having any wobble was not acceptable.. I didn’t have to measure the runout to see how bad these were it was visible. They’re definitely not appropriate for a 3D printer.

Sort of small

After a few uses the coupler was stripped and kept coming off the z motor.

Should work fine on a 3d printer, but its horrible on a CNC machine.

The plastic slides right out whether vertical or horizontal. The bottom of the clamping screw hole was foil thin. it wouldnt clamp on the stepper shaft

works great for helping z axis stress. Printer moves much smoother now after this and a dual axis upgrade

I could not get my Z axis screw drive to remain level with the vertical frame of my Ender 3 V2. This little gem solved the issue as the gel inserts between the lower and upper halves allow flexing and the Z axis rod now remains straight. Great solution for a minor issue. 2 sets to a pack so youll always have a spare on hand.