Production of the Lambda in significant numbers began in 1921. It was the first mass-produced car to be equipped with brakes on all four wheels and to have unibody construction. It was also the first automobile to be provided with an independent front suspension and to have a floor with a central tunnel for the driveshaft. The latter innovation made a lower center of gravity and a lower seating level possible. It also helped enhance the car's rigidity and styling. Another Lambda "first" was a trunk (or boot) that was part of the body. By 1925, the Lambda had a four-speed transmission and an overhead-valve V4 engine. It took other manufacturers at least a decade to adopt this automobile's innovations. (Information provided by the museum.)