In 1962, the MG B introduced a new era of affordable lightweight four-cylinder roadsters. The MG B used a unibody construction and was produced until 1980. Other successful lightweight roadsters include the Triumph Spitfire (1962-1980) and the Alfa Romeo Spider (1966-1993). The Fiat X1/9 (1972-1989) was unusual for its use of a mid-engine design in an affordable roadster model. A late entrant to the affordable roadster market was the 1975 Triumph TR7, however by the late 1970s the demand for this style of car was in decline, resulting in production ceasing in 1982.