This is the Hitec High Votage D645MW High Torque Metal Gear Servo. The metal D-645MW is part of Hitec's D-Series servo line. All Hitec D-Series servos have been designed using Hitec's redesigned, cutting edge, custom engineering. Combining industry leading high-resolution, state-of-the-art ultra-response technology with a 32-bit MCU and 12-bit ADC for unprecedented programmability and flexibility, these servos deliver significantly smoother movement. The speedy, powerful line operates on a wide 4.8 ~ 8.4 voltage range, allowing use with any common battery chemistry without the need for adapters or regulators. Featuring Hitec’s industry standard 25-tooth output spline with 3mm hex screw, each D-Series servo brings monster performance never known before in the market. Features: Programmable PWM Digital Amplifier 32-Bit MCU with 12-Bit ADC Circuitry 4096 Resolution 1M Cycle Long Life Potentiometer Wide Operating Voltage (4.8 ~ 8.4 Volts DC) Dual Ball Bearing Supported Output Shaft 25-Tooth Output Spline Programmable Functions: End Point Adjustments Direction Fail Safe Dead Band Speed (Slower) Soft Start Rate Overload Protection Data Save / Load Program Reset Specifications: Operating Voltage Range (Volts DC): 4.8V ~ 6.0V ~ 7.4V Speed (Second @ 60°): 0.28 ~ 0.20 ~ 0.17 Maximum Torque Range oz./in.: 115 ~ 158 ~ 180 Maximum Torque Range kg./cm.: 8.3 ~ 11.3 ~ 12.9 Current Draw at Idle: 30 mA No Load Operating Current Draw: 500 mA Stall Current Draw: 2,650 mA Dead Band Width: 2 µs Dimensions (Inches): 1.59 x 0.77 x 1.48 Dimensions (Metric): 40.6 x 19.8 x 37.8 Weight (Ounces): 2.11 Weight (Gram): 57.0 Circuit Type: 32bit Programable Digital Motor Type: 3 Pole Metal Brush Ferrite Gear Material: Metal Bearing Type: Dual Ball Bearing Output Shaft (type / Ømm): H25T Case Material: Plastic Dust/Water Resistance: N/A Connector Gauge (AWG)/Strand Count: 22/60 Accessories: Metal Gears Set Metal Plastic 1st Gear Set Plastic Case Set Applicable Horns