This is the Savox SC-1257TG Super Speed Titanium Gear Digital Servo.

Features:

Combines leading edge technology with super high 12 bit (4096) resolution and titanium gears.
Super light-weight.
Coreless motor provides high speed, incredible efficiency, and low power consumption.
Extremely strong titanium gears.
The aluminum case design not only looks good but also allows for lower operating temperatures.
Our servos are totally green – from materials to production, these servos are environmentally friendly.
Ideal for CCPM on 600 and 700 class heli, steering servo on 1/10 scale buggies.

Dimensions(mm): 40.3x20.2x37.2
Weight(g): 52.4
Speed(@4.8V sec/60): .09
Torque(@4.8V oz-in): 111.1
Speed(@6.0V sec/60): .07
Torque(@6.0V oz-in): 138.9
Gear: Titanium & Aluminum
Bearing: 2BB
Case: Aluminum
25 Tooth Spline