This is a Vigor VTS08B servo motor. It is small, and offers good power for its size. This servo is - 43×23×38.2mm big, 43g and develops a stall torque of more than 5 kgf.cm . The servo comes with 3 different horns with mounting holes. 

Operating Voltage    :  4.8-6.0 V

PWM Input Range    :  Pulse Cycle 20±2ms, Positive Pulse 1~2ms

STD Direction          :  Counter Clockwise / Pulse Traveling 1500 to 1900µsec

Stall Torque              :   5Kgf.cm (69.5 oz/in) at 4.8V, ?6Kgf.cm (83.4 oz/in) at 6V 

Operating Speed       :  0.33 sec/ 60° at 4.8V, 0.3 sec/ 60° at 6V at no load

Weight                        :  43g (1.5 oz)

Size                             :   43 x 23 x 38.2 mm (1.69 x 0.91 x 1.5 in)

Plug Available           :   FUT, JR

Special Feature:       :    Heavy Duty Plastic Gears , Economy Servo 

Datasheet:-

http://www.vigorprecision.com.hk/uploadfile/20120530/20120530173638250.p