This is the Futaba S3156 Micro Digital Metal Gear Servo.

FEATURES: For small electric powered aircraft models

INCLUDES: Futaba S3156 servo, 0.79" (20mm) long 4-point horn, 1.6" (40mm) long
            4-point horn, 0.79" (20mm) diameter round horn, four 2x11mm
            mounting sccrews
          One year limited warranty

REQUIRES: Installing in model, connecting linkage and connecting to receiver
          Order DUBM6924 if mounting hardware is needed

SPECS:    Torque: 28 oz-in (2.0 kg-cm) @ 4.8V
                  33 oz-in (2.4 kg-cm) @ 6V
          Speed: .13 @ 4.8V
                 .11 @ 6V
          Size: 0.9 x 0.4 x 0.9" (22 x 11 x 22mm)
          Weight: .32 oz (9.3g)

COMMENTS: Do not use this servo with gas powered models or models requiring
            high torque.
          Do not exceed 6V supply voltage or apply high load to servo.
          Do not use standard size servo horns. Use horns designed only for
            micro servos.
          For replacement horns use part numbers FUTM2005 or FUTM2038, they
           fit very tight but they will work.
                                                                    jxs 2/12/08
                                                                         ir/jxs
                                                             updated jpg 6/9/08