Build a Single Gear Racer from over 180 VEX Robotics Pieces! This construction kit challenges you to build a pull back VEX Robotics Single Gear Racer! This Single Gear Racer teaches you about how machines convert potential energy into kinetic energy, while the multiple gear ratios teach you about the fundamental principles behind speed and torque. Pull back and release the fun with the VEX Robotics Single Gear Racer by HEXBUG. Kids can now experience the fun of building their own speedy robot-inspired cars with VEX Robotics Single Gear Racer by HEXBUG?! Single Gear Racer work by pulling back the car and the resistance lever raises to generate tension from the rubber bands. The VEX Robotics Single Gear Racer include multiple gear sets, rubber bands, wheels and all the pieces needed to build a powerful racer!