This is the Futaba High Voltage BLS172SV S.Bus2 UHT
Programmable Metal Gear Servo.

FEATURES
Brushless motor offers incredible holding power and 5X longer life than servos equipped with brushed motors.
Ultra high torque
Handles up to 2S LiPo power
Programmable and compatible with S.Bus and S.Bus2
Dual ball bearing supported output shaft
The center and bottom case are aluminum to help dissipate heat.
INCLUDES
HV BLS172SV UHT S.Bus2 Servo with Instructions
0.83" (21mm) Round Horn
1.8" (45mm) Round Horn
1.5" (39mm) Four Point Horn
1.2" (32mm) Six Point Horn
Four each, Grommets, Eyelets and Mounting Screws

SPECIFICATIONS
Torque: 514 oz-in (37 kg-cm) @ 7.4V
Speed: 0.11 sec/60° @ 7.4V
Dimensions: 1-9/16 x 13/16 x 1-1/2" (41 x 21 x 38mm)
Weight: 2.6 oz (74 g)
SBus Programmable Defaults
Dead Band Degree: 0.36
Damper Factor: 128
Stretcher Gain: 1
Boost: 5
Neutral Offset Degree: 0
Travel Adjust Percentage: 100%
Reverse (Normal/Reverse): Nor
Stop Mode (Free/Hold): Hold
Buzzer (On/Off): Off
Smoother (On/Off): On
Boost (On/Off): Off
Soft Start: 3.0