This is the Futaba High Voltage BLS173SV S.Bus2 HV SX Mini Servo.

Designed to be used with models requiring high speed and high torque
Brushless motor offers incredible holding power and 5X longer life
than servos equipped with brushed motors
Programmable and compatible with S.Bus and S.Bus2
One year limited warranty through Hobby Services beginning at date of
purchase

HV BLS173SV HS S.Bus2 Mini Servo with Instructions
0.83" (21mm) Round Horn
1.5" (39mm) Four Point Horn
1.2" (32mm) Six Point Horn
Four each, Grommets, Eyelets and Mounting Screws

Torque: 105.6 oz-in (7.6 kg-cm) @ 7.4V
94.5 oz-in (6.8 kg-cm) @ 6.6V
Speed: 0.10 sec/60° @ 7.4V
0.11 sec/60° @ 6.6V
Dimensions: 1.30 x 0.59 x 1.07" (33 x 15 x 27.1mm)
Weight: 0.99 oz (28 g)
Power Requirements: DC 6V to 7.4V

SBus Programmable Defaults
Dead Band Degree: 0.36
Damper Factor: 112
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