This is the Hitec HS-55 Sub Micro (Feather) Servo with a Futaba J, Hitec S, JR, Airtronics Z-type Connector.

• Very slim case and lightweight for mounting in small airplanes, electrics or gliders, where very high speed and good torque are critical.
• One of the slimmest micro servos available.
• High-strength resin gear train provides reliable operation.

• One HS-55 Servo w/pre-installed small X-shaped servo horn and screw
• One very small straight servo horn
• One M1.7x3 servo horn screw
• One small straight servo horn
• Two M1.7x7 servo mounting screws at 4.8V

• Speed: 0.17 sec at 60 degree
• Output Torque: 15.27 oz-in (1.1 kg-cm)
• Weight: 0.27oz (7.8g)
• Length: 0.89" (22.8mm)
• Width: 0.45" (11.6mm)
• Height: 0.94" (24mm)