This is the Axial 25T Aluminum Servo Horn for Futaba, Axial and Savox Servos.
Features:
Includes: Axial 25T aluminum servo horn and two 2x8mm socket head screws
Specs:
Length: 0.98 (25mm) from center of servo mounting hole to end of arm
Hole Diameter: 3mm
Pitch: 3x30
Material: Aluminum