Servo: SF-50 Metal Gear (12kg)HP 102777B HPI Racing HPI SF 50 SERVO(METAL GEAR 12kg cm6. 0V) This high torque SF 50 Servo is a direct replacement for the SF 5 servo found on HPI trucks and buggies. High torque and a tough metal output gear give it the strength needed for applications like the steering of the Savage XL and Vorza Flux. If you're looking for more torque, the SF 50 is an easy bolt in upgrade for the HPI SF 1, SF 10, SF 2, SF 20 servos. It's the ideal option to replace