Sport 18" Suitcase Frame Color: Black Aluminum Alloy Frame/Premium Water-Resistant 600D Polyester Aluminum alloy frame rated to hold up to 300 lbs and doubles as a built-in seat The dual wheel system climbs stairs and curbs with ease Magneto dynamic 4" polyurethane wheels absorb shock and make for a serious silent ride Wheels flash and powered by a tiny generator so there are no need for batteries