The motor shield is based on the L298 , it is a double complete bridge driver designed to drive inductive loads, such as relays, solenoids, DC and stepper motors.
This is a DC motor with and metal gear with encoder . It is a 6V engine with a 20: 1 metal gearbox and an integrated quadrature encoder that offers a resolution of 11 counts per revolution.
This module is based on the popular L298N H Bridge DC Motor Driver . The circuit will allow you to easily and independently control two motors up to 2A each in both directions.