This is the Savox SV-1272MG Monster Torque High Voltage Unique Steel Gear Digital Servo-savsv1272mg.

Features:
Extremely powerful for its size pushing 416.6 oz-in torque.
Super strong and precision made unique steel gears provide high level of durability and survives heavy use.
Coreless motor brings output performance to the top level – smoother, faster, and more efficient.
Special design for high voltage native 2s LiPo operation.
Water-proof with 4 silicon seals.
Our servos are totally green – from materials to production, these servos are environmentally friendly.
Ideal for large-scale airplane, jet, and 1/5th scale surface.

Dimensions(mm): 40.3x20.2x37.2
Weight(g): 63.0
Speed(@6.0V sec/60): .13
Torque(@6.0V oz-in): 319.4
Speed(@7.4V sec/60): .10
Torque(@7.4V oz-in): 416.6
Gear: Unique Steel
Bearing: 2BB
Case: Aluminum
25 Tooth Spline