This is the HS-7945TH High Volt, Mega Torque, Metal Gear Servo from Hitec.
FEATURES: Ideal for high performance aircraft, cars, trucks and larger nitro
and electric helicopters where high speed and high torque are
needed
7.4V optimized coreless motor designed to be powered from a 2S LiPo
battery for extra speed and power (may also be powered by
conventional NiCds)
Durable titanium alloy metal gears with dual ball bearing output
shaft (MK first gear)
Programmable features include; Dead Band Width, Rotation Direction,
Rotation Speed, End Points/Neutral Points, Fail Safe On/Off, Fail
Safe Point, Resolution and Overload Protection (requires Hitec
programmer HFP20, HPP20 or HPP21)
Eight O-rings for water, dust and fuel resistance
Heatsink case
INCLUDES: HS-7945TH High Volt Mega Torque Metal Gear Servo with Connector,
1.8" (45mm) round horn, 1.2" (27mm) single arm, 2.3" (59mm) double
arm, 2.8" (72mm) double arm, 1.3" (33mm) single arm, 0.87" (22mm)
aluminum single arm, mounting hardware and instruction sheet
REQUIRES: Installing in model and connecting linkage
SPECS: Motor Type: Coreless (7.4V wind)
Bearing Type: Dual ball bearing
Speed: 6.0V, 0.12 sec/60°
7.4V, 0.10 sec/60°
Torque: 6.0V, 250 oz-in (18.0 kg-cm)
7.4V, 319 oz-in (23 kg-cm)
Size: 1.57 x 0.79 x 1.5" (39.88 x 20.07 x 38.10mm)
Weight: 2.40oz (68g)
COMMENTS: A note on coreless motors-a conventional servo motor has a steel core
armature wrapped with wire that spins inside the magnets. In a
Coreless design, the armature uses a wire mesh that forms a cup
that spins around the outside of the magnet. This arrangement is
much lighter resulting in smoother operation and faster response
time.