Wild Thumper 6WD Chassis - Black (34:1 gear ratio) by SparkFun "Super Twist" suspension keeps all your tires on the ground even on rough terrain Spiked 120mm off-road wheels are super 'grippy' 6 x 7.2v DC motors with 34:1 steel gearboxes 10mm pitched mounting holes. Made from sturdy 2mm thick plate aluminum Recommended voltage: 2-7.5v