The ThunderJet 500 chassis is Auto World's adaptation of the classic "pancake" design, originally developed by Aurora in the early days of electric slot racing. Still immensely popular today, entire slot racing events are created around this chassis. It continues to be a favorite with collectors and hardcore drivers. ThunderJet bodies mount over the chassis using two small screws. ThunderJets are retro slot racing at its best! The '68 Mercury Cougar iWheels were produced in very limited numbers.