This is the Savox SC-0251 High Torque Metal Gear Digital Servo. Features: Precision metal gears form a strong and solid framework Strict production and quality control of plastic components ensures high performance Our servos are totally green – from materials to production, these servos are environmentally friendly. This high torque servo is great for crawlers, 1/8 scale vehicles and 50 class airplanes. Dimensions(mm): 40.7X19.6X42.4 Weight(g): 61.0 Speed(@4.8V sec/60): .20 Torque(@4.8V oz-in): 180.5 Speed(@6.0V sec/60): .18 Torque(@6.0V oz-in): 222.2, 16kg.cm Gear: Metal Bearing: 2BB Case: Plastic 25 Tooth Spline Frequency: 200-250hz Pulse Width Frequency: 1520