24t

A Servo to Shaft Coupler offers a simple and solid way to attach a shaft in line with the output spline of a servo! Available in both 24 Tooth (C1) Spline and 25 Tooth (3F/H25T) Splines. https://www.servocity.com/servos/servo-accessories/servo-attachments/couplers/clamping-servo-to-shaft-couplers