Zeberoxyz 2PCS 8mm to 10mm Aluminium Plum Flexible Shaft Coupling Diameter20mm Length25mm 8x10mm Motor Connector Flexible Coupler for 3D Printer CNC Machine and Servo Stepped Motor（8x10mm）

Good product. Worked great.

I built a Z-Axis lift for my Precision Matthews tabletop mill and was getting serious vibrations from the gearbox to the Z-axis linkage. This looked a little flimsy to me at first, but has been working like a champ for over a year now in frequent use.

These couplers do not work well on US standard .25" shaft. They tend to slip due to the fact they are 6.5mm not exactly .25 ". I switched the shafts to 6.5mm nd they work fine. The couplers are good quality for the price !

They are exactly as described and work well. Strong and durable.

If your Z-rod is slipping on your Ender 3 Pro, these are a great replacement

Yeah, I definitely crashed a head while fighting with a difficult print. These easy-break away features saved me from doing much more damage.

Not great. The coupling can be pulled apart by hand. If your two shafts exert tensile force (i.e., are pulling apart) along their axis then this coupling can fail. I wanted to use this to turn a lead screw which supports a panel that contracts and extends. This exerts an axial force on the coupling. I reinforced the coupling too with a 8-32 lead screw to ensure the motor shaft and the lead screw are fixed securely to the coupling.

Works like a charm