Joysway Superior 551 USB Power Slot Car Racing set comes with a USB power system. It is the first and most innovative application in slot car toys industry. Traditional slot racing set is powered by batteries or transformer. With Joysway slot racing set, you can use the supplied USB power cable to connect your own power bank (Output:5V2A) or smart-phone USB power adapter (Output:5V2A). Joysway USB power slot racing set is user-friendly. Details:17.32" x 4.72" x 24.41"Includes 2 carsFor ages 8 and ups