This is the HS-7940TH High Speed, High Torque Digital Servo from Hitec.

FEATURES: Ideal for larger helicopters and cars needing high speed and plenty of torque Coreless motor for precise centering and accuracy G2 programmable digital circuit, programmable features include; Dead Band Width Speed (reduction) Fail Safe Position Direction (CW/CCW) Fail Safe On/Off End Points Overload Protection Resolution High/Low Titanium gears don't break or develop slop like conventional metal gears Capable of operating on two LiPo packs

INCLUDES: HS-7940TH High Speed, High Torque Digital Servo

REQUIRES: Installing in model and connecting to control linkage and receiver

SPECS: Size: 1.57 x 0.79 x 1.50" (40 x 20 x 38mm) Weight: 2.40oz (68g) 6.0V 7.4V Speed: 0.07 sec 0.06 sec Torque: 181 oz/in (13.0kg/cm) 222 oz/in (16.0kg/cm) Drivetrain Type: Dual ball bearing

COMMENTS: This servo can be programmed with any Hitec digital servo programmer. However, the Overload Protection and Resolution High/ Low can only be programmed with the HFP-20, HPP-21 (HRCM4420) or the HPP-21+ (HRCM4421) 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.  

BOX DIMENSIONS: 3.00" W. X 1.38" H. X 3.75" L. BOX WEIGHT: .29 LBS.