This is the Hitec D845WP Waterproof Monster Torque Mega Servo.
Wide voltage DC 3.5-8.4V operation
Ideal for airplanes, giant scale car, boat, UAV and robotics
Programmable high response digital amplifier with MOSFET drive
(requires Hitec Servo Saver sold separately)
Steel gears with dual ball bearing supported output shaft
Center case section is a heat sink
Hitec D845WP Servo with Wire Lead and Connector
(39.8mm) Round Nylon Horn
(46mm) Single Arm Nylon Horn
(55mm) Double Arm Aluminum Horn
(61mm) 4-Point Nylon Horn
Four each Grommets, Eyelets and Mounting Screws
4.8V 6.0V 7.4V
Speed: 0.26 sec/60° 0.21 sec/60° 0.17 sec/60°
Torque: 453.82oz-in 565.53oz-in 698.19oz-in
32.5kg-cm 40.5kg-cm 50kg-cm
Weight: 8.0oz (227g)
Dimensions: 2.59 x 1.26 x 2.44" (66 x 32 x 62mm)