Save yourself the hazzle with z axis calibration and broken plastic couplings due to radial offset. This solid shaft coupling can be mounted easily with two grub screws on each side.
Length: 25 mm Outer diameter: 20 mm d1: 5mm d2: 8mm
Delivery content: 1 piece incl. grub screws
Attention: You need 2 pcs. for your Prusa 3D printer.