This is the MKS HV93 Metal Gear Micro Digital High Voltage Servo.

Specifications:
Dead Band: 0.001ms (Default)
Control System: +Pulse Width Control
Working Frequence: 1520?s / 333hz
Operating Voltage: 3.8~8.4 V DC Volts
Operating Speed (6V): 0.07 sec/60° degrees at no load
Operating Speed (8.4V): 0.05 sec/60° dagrees at no load
Stall Torque (6V): 31.25 oz/in (2.25 kg-cm)
Stall Torque (8.4V): 44.44 oz/in (3.2 kg-cm)
Motor Type: Coreless Motor
Potentiometer Drive: Direct Drive
Bearing Type: Dual Ball Bearings
Gear Type: Chrome-Titanium alloy gear
Programmable: No
Dimensions: 23x12x27.25 mm (0.9x0.47x1.07 in)
Weight: 19.87 g