This is the Savox SC0253MG Metal Gear Digital Servo.

Features:
Budget Digital Upgrade
Precision metal gears forms a strong and solid framework
Strict production and quality control of plastic components ensures long life and durability
Our servos are totally green – from materials to production, these servos are environmentally friendly.
Ideal for 30 size airplane or steering on 1/8th scale buggies.
Dimensions(mm): 40.7X20.0X37.0
Weight(g): 59.0
Speed(@4.8V sec/60): .17
Torque(@4.8V oz-in): 55.5
Speed(@6.0V sec/60): .15
Torque(@6.0V oz-in): 83.3
Gear: Metal
25 Tooth Spline
Bearing: 1BB
Case: Plastic
25 Tooth Spline