Jet-Ski is the bran name of personal watercraft (PWC) manufactured by Kawasaki Heavy Industries, Ltd.. The name, however, has become a genericized trademark for any type of personal watercraft. Jet ski (or jetski, often shortened to "ski") can also specifically refer to versions of PWCs with pivoting handlepoles known as "stand-ups". Jetski became foremost the colloquial term for stand-ups because, in 1973, Kawasaki was responsible for a limited production of stand-up models as designed by the recognized inventor of jet skis, Clayton Jacobsen II. In 1976, Kawasaki then began mass production of the JS400-A. JS400s came with 400 cc two-stroke engines and hulls based upon the previous limited release models. It became the harbinger of the success Jet-Skis would see in the market up through the 1990s. In 1986 Kawasaki broadened the world of Jet Skis by introducing a two person model with lean-in "sport" style handling and a 650cc engine, dubbed the X-2. Then in 1989, they introduced their first two passenger "sit-down" model, the Tandem Sport (TS) with a step-through seating area. For 1992 Kawasaki updated their standup line with the JS750 featuring a more stable hull and more power.In 2003, Kawasaki celebrated the Jet Ski brand by releasing a special 30th anniversary edition of its current stand-up model, the SX-R, which has seen a revival of interest in stand-up jetskiing. The X-2 has also been updated, based on the SX-R platform and re-released in Japan. Kawasaki continues to produce three models of sit-downs, including many four-stroke models. The four stroke engines have come on since the late 1990s; with the help of superchargers and the like the engines can output up to 250 horsepower as seen in the newly released Kawasaki ultra 250x . Since jetskiing has evolved through the 90s other companies like Yamaha, Bombardier and Polaris have joined the sport to make it into a worldwide sport in both racing and freestyle.