This is the Futaba S3114 Micro High Torque Servo.

Features:
Ideal for electric planes and small electric helis
Nylon gears
One year warranty

Includes:
Futaba S3114 Micro High Torque Servo One .91" x .64" (23mmx16mm) 4 arm servo horn (comes pre-installed)
One 1.33" x 1.33" (34mmx34mm) 4 arm servo horn

Requires:
Installing in aircraft and connecting to receiver

Specs:
6V 4.8V
Torque: 23.5 oz-in (1.7 kg-cm) 20.8 oz-in (1.5 kg-cm)
Speed: .09 sec/60° .10 sec/60°
Dimensions: .86 x .43 x .78" (21.8 x 11 x 19.8mm)
Weight: .27oz (7.8g)
Lead Length: 6.5" (165mm)
Output Spline Diameter: 4mm