The first commercial 707s, labeled the 707-120 series, had a larger cabin and other improvements compared to the Dash 80 prototype. Powered by early Pratt & Whitney turbojet engines, these initial 707s had range capability that was barely sufficient for the Atlantic Ocean. A number of variants were developed for special use, including shorter-bodied airplanes and the 720 series, which was lighter and faster with better runway performance.