Brand: AutomationDirect Item: Encoder coupling For Use With: JTEKT TRD-MX series encoders and NEMA size 23 stepper motors Length: 23mm Body Material: Aluminum alloy Bore: 4mm to 1/4in Attachment Style: Setscrew AutomationDirect encoder coupling, 4mm to 1/4in bore, aluminum alloy body, setscrew. For use with JTEKT TRD-MX series encoders and NEMA size 23 stepper motors.