Review on Xnrtop Coupling Diameter Aluminum Connector by Hector Smith

This was the only 5mm x 8mm flexible coupling I could find that used split jigs instead of set screws holding the shafts can damage. Couplings are carefully crafted - accurate and coaxial diameters, clean cuts and chamfers, smooth threads. Very good quality - compensates for any misalignment with your shafts.