1pcs BR 3mmx3mm D20L25 CNC Motor Shaft Coupler 3mm to 3mm Coupling connect servo motor stepper motor encoder BR series flexible coupling CNC Motor shaft coupler Body Material: Aluminum Alloy Max torque: 1N.m Rated Torque(N.m) :0.5N.m Eccentricity error: 0.2mm Shaft angel  2 Max Rotational (rpm) :19000 Rated: In-phase operate D=20 L=25 d1=3 d2=3