Brand: AutomationDirect Item: Encoder coupling For Use With: JTEKT TRD-MX series encoders and NEMA size 17 stepper motors Length: 19.1mm Body Material: Aluminum alloy Bore: 4mm to 5mm Attachment Style: Setscrew AutomationDirect encoder coupling, 4mm to 5mm bore, aluminum alloy body, setscrew. For use with JTEKT TRD-MX series encoders and NEMA size 17 stepper motors.