Image Item No. Description  26021  Vehicle, Base 4 x 5 Roller Coaster Car Catalog: Parts: Vehicle, Base  26021c01 (Inv)  Vehicle, Base 4 x 5 Roller Coaster Car with Dark Bluish Gray Wheels (26021 / 24869) Catalog: Parts: Vehicle, Base  30837  Vehicle, Base 4 x 8 x 1 1/3 Catalog: Parts: Vehicle, Base  30842  Vehicle, Base 4 x 14 x 1 with Tow Ball Socket Hitch (Semi Tractor) Catalog: Parts: Vehicle, Base  28324  Vehicle, Base 6 x 12 with 4 x 2 Recessed Center with Smooth Underside Catalog: Parts: Vehicle, Base  30833  Vehicle, Base 6 x 21 x 3 Catalog: Parts: Vehicle, Base