This is a CNC machined flexible coupling that is ideal for connecting the Z-axis screws to the stepper motors on a Prusa-Mendel i3 Reprap type 3D Printer
One 5mm bore is for the output shaft of a NEMA17 stepper motor and the other 5mm bore is for the M5 threaded rod.
The coupling is made of Aluminium.
Diameter = 20mm
Length = 25mm
Weight = 17g
The price is for 1 coupling.