A mini 4WD is a 1:32-sized battery

Battery (electricity)

An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

 powered plastic model race car without remote control

Remote control

A remote control is a component of an electronics device, most commonly a television set, used for operating the television device wirelessly from a short line-of-sight distance.The remote control is usually contracted to remote...

. All 4 rubber-tired wheels are driven, thus "4WD" for 4 wheel drive. Side rollers secure the vehicle against the vertical walls of the un-banked track for steering, providing very fast speeds compared to slot

Slot car

A slot car is a powered miniature auto or other vehicle that is guided by a groove or slot in the track on which it runs. A pin or blade extends from the bottom of the car into the slot...

 or RC cars

Radio-controlled car

Radio-controlled cars are self-powered model cars or trucks that can be controlled from a distance using a specialized transmitter...

. In Japan, Mini 4WD is also known as mini yonku (ミニ四駆) in Japanese. Though mostly popular in Asia, they have also been sold in the United States.
Mini 4WD was first created by the Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese company Tamiya in 1982 as a powered variant of common plastic automobile model kits.