NEW KAWASAKI JET SKI ULTRA 300X. SUPPLY CLEARANCE SALE. DONT MISS OUT ON THIS NEW JET SKI ULTRA 300X !!!!! Its 1,498 cc engine is enhanced by a sophisticated Eaton TVS supercharger and Kawasaki's Digital Throttle Valve Device to assist network power exactly where and how the rider desires it. The Ultra 300X's race-derived hull delivers the top-tier handling that hardcore lovers expect.