Large Plastic Project Wheels And Axles, For Mousetrap Car And Rubber Band Car Projects, 20 Wheels, 20 Rubber Bands, 10 DowelsIf You'Ve Ever Tried To Build A Rubber Band Powered Car Using, You'Ll Know That The Wheels Are The Most Challenging And Crucial Material. Plastic Bottle Caps Are Too Small, And Cds Are Difficult To Attach To An Axel. These Large Project Wheels Are Designed Specifically For Educators, Parents, And Makers Who Want To Build Vehicles That Work The Way You Expect. The 4. 75'' Wheel Diameter Helps Your Projects Go The Distance, And The Included Rubber Bands