Power HD LW-20MG Standard Size servo. FEATURES: Plastic waterproof blue case Specs: Torque(4.8V): 229.1oz/in (16.5 kg-cm) Torque(6.0V): 277.7oz/in) (20.0 kg-cm) Speed: 0.18 sec (4.8V)‚ 0.16 sec (6.6V) Operating Voltage 4.8 ~ 6.6 DC Volts Weight: 60 g (2.12 oz) Bearing Type: Ball Bearing x 2 Motor Type: DC Motor Gear Type: Copper & Aluminum Working frequency: 1520μs / 333hz Size: 40.7 x 20.5 x 39.5 mm ( 1.60 x 0.80 x 1.55 in) Servo arm type: Futaba Note: When the digital steering gear is subject to resistance will be issued a continuous creak current sound, the greater the resistance sound the more loud, this is a normal phenomenon. Not for use underwater.