This 143:1 gearmotor (gearbox with brushed DC motor) is a faster version of the GM3 gearmotor. It is a great low-cost alternative to modified hobby servos or Tamiya gearboxes. The low-current motor is a perfect match for the qik 2s9v1 dual serial motor controller from Pololu, and the compact size makes this unit an attractive choice for small robot designs.