GWS Mini Park Series Servo.
(smaller than a standard size servo, though larger than Nano/Pico Servos)
Model: PARK HPX
Size: 30.86x16.17x28.5
Weight: 19g
Speed: (4.8v: 0.07sec)(6v: 0.05sec)
Torque: (4.8v: 3kg)(6v: 3.6kg)