This is the JR Sport ST47BB Standard Ball Bearing Servo.  This servo has a universal connector that works with JR, Hitec, Futaba, and Airtronics.

Specifications:
Size Category: Standard
Type: Analog
Torque: 47 oz/in @ 4.8V
Speed: .18/60 @ 4.8v, .15/60 @ 6v
Dimensions (WxLxH): 0.73 x 1.52 x 1.32
Weight: 1.55 oz
Bushing Or Bearing: Bearing
Gear Type: Nylon
Application: .40- to .90-size Aircraft