This is the Tactic TSX55 Ultra Torque Metal Gear Servo.

FEATURES

Metal gear train with two ball bearings
Universal receiver connector compatible with all major brands of
radio systems
One year limited warranty through Hobby Services beginning at date of
purchase

Tactic TSX55 Ultra Torque Metal Gear Servo
0.82" (20.8mm) diameter Round Horn
1.5" (38mm) 4-Point Horn
1.2" (31.9mm) 6-point horn
Four each, rubber Grommets, Eyelets, and 2.3 x 14mm Mounting Screws

4.8V 6.0V
Torque: 181 oz-in (13.1 kg-cm) 203 oz-in (14.6 kg-cm)
Speed: 0.24 sec/60° 0.21 sec/60°
Dimensions: 1.6 x 0.8 x1.5" (40 x 20 x 38mm)
Weight: 2.1 oz (58 g)