This is a micro size servo motor metal gears. Metal gears provide strength/torque at the cost of higher weight and quicker wear-out. This servo motor gives stall torque of 1.8 Kg.cm at 4.8V and 2.2 Kg.cm at 6V. This is a good contender for small RC toys and robots.
Servo motors are a type of brush DC motors with some extra features that make them ideal for use in robotics and in RC planes. Servo motors are used for angular motion and we can accurately know the angle in which the motor is rotated at any particular point. Most commonly servo motors rotate 90º on either side from the central starting point.