This is the Futaba S3051 HV High Voltage High Torque Standard Servo.

FEATURES: Digitally enhanced microprocessors cut in half the response time
            from transmitter input to servo reaction
          Standard size servo offers high torque and high speed
          One year limited warranty through Hobby Services beginning at date of
            purchase

INCLUDES: Futaba S3051 HV High Voltage High Torque Standard Servo with 0.83"
            (21mm) Round Horn, 1.4" (35.2mm) Round Horn 1.5" (38.5mm) 4-Point
            Horn, 1.2" (31.9mm) 6-Point Horn, Mounting Hardware and
            Instructions

REQUIRES: Installing in model, attaching linkage and plugging into receiver

SPECS:    Speed: 0.21 sec/60° @ 6.0V
                 0.19 sec/60° @ 6.6V
                 0.17 sec/60° @ 7.4V
          Torque: 132.0 oz/in (9.5 kg/cm) @ 6.0V
                  138.9 oz/in (10.0 kg/cm) @ 6.6V
                  145.8 oz/in (10.5 kg/cm) @ 7.4V
          Size: 1.57 x 0.79 x 1.50" (40 x 20 x 38.1mm)
          Weight: 1.73 oz (49 g)
          Power Supply: 6.0 - 7.4V DC
          Hron Screw Size: 3x8mm

                                                                   jxs 08/22/11
                                                                         ir/jxs