Brand: AutomationDirect Item: Encoder/stepper coupling For Use With: JTEKT TRDA-20 and TRDA-25 series encoders and NEMA size 34 stepper motors Length: 38mm Body Material: Engineered polymer Bore: 3/8in to 1/2in Attachment Style: Setscrew AutomationDirect encoder/stepper coupling, 3/8in to 1/2in bore, engineered polymer body, setscrew. For use with JTEKT TRDA-20 and TRDA-25 series encoders and NEMA size 34 stepper motors.