The servo rudder you are looking for is here, all sizes and mounting types are available!
Reference 02RC15201-BLK
Brand: RC PARTS
ALU CLAMPING SERVO HORN BLACK (25T - 24mm) - RC15201-BLK
Reference 08293441
Brand: HUDY
ALU CLAMP THROTTLE SERVO HORN - KO , SANWA - OFFSET 2-HOLE M3 - 23T-2
Reference 08293442
Brand: HUDY
ALU CLAMP THROTTLE SERVO HORN - HITEC - OFFSET 2-HOLE M3 - 24T - 2934
Reference 08293447
Brand: HUDY
ALU CLAMP THROTTLE SERVO HORN - KO PROPO, SANWA - 2-HOLE M3 - 23T - 2
Reference 08293448
Brand: HUDY
ALU CLAMP THROTTLE SERVO HORN - HITEC - 2-HOLE M3 - 24T - 293448
Reference 05FAST310B
Brand: FASTRAX
23T BLACK ALUMINIUM SERVO HORN (KO/SANWA) - FAST310B
Reference 08293421
Brand: HUDY
ALU CLAMP STEERING SERVO HORN - EXTENDED 8mm - 23T - 293421
Reference 02UR1803
Brand: ULTIMATE
ALUM.STEERING SERVO HORN FOR FUT/POW HD 25T (1pc.) - UR1803
Reference 02UR1806
Brand: ULTIMATE
ALUMINIUM DOUBLE ARM SERVO HORN (25T - FUTABA/SAVOX/ORION) (1pc.)-UR1
Reference 09C-10112
Brand: CORALLY
TEAM CORALLY - SERVO SAVER - S MALL - 21 SPLINE - NOVAK NES-1 - C-101
Reference 09C-10113
Brand: CORALLY
TEAM CORALLY - SERVO SAVER - SMALL - 23 SPLINE - SANWA - JR - C-10113
Reference 09C-10122
Brand: CORALLY
TEAM CORALLY - SERVO SAVER - LARGE - UNIVERSAL - DOUBLE END - C-10122