Build the derby car of your derams with the SUPER BLOCK X 125: The body block is the foundation of any blazing fast car and Derby Champ's features holes drilled for perfect rear weight placement using our Slotted Tungsten Round (product #716) Weight that fit perfectly into the large center hole, and precision drilled axle holes for an extended wheelbase with 4 wheels on the track. Perfect or those who want to race with 4 wheels on the track. For a 3 wheeler (faster) we recomend the SUPER BLOCK X 127. Wheels and axles are sold separately to give your car that winning edge!