Product Description Overview These ½ arms are drilled for 3mm-linkage hardware and offer maximum steering control, as well as instantaneous throttle and brake response by eliminating the flex you often get with nylon and plastic servo arms. The “full” arms have drilled holes, as well as a larger hole(s) to house a wide range of throttle and brake linkage requirements. Specs Servo Arm Style: Double Servo Arms : Futaba