The Land Rover series I, II, and III , or simply the Land-Rover (commonly referred to as series Land Rovers, to distinguish them from later models) are compact British off-road vehicles, produced by the Rover Company since 1948, and later by British Leyland. Though inspired by the World War II jeep, the Land Rover immediately distinguished itself from all other cars. From launch, it was the first mass-produced civilian four-wheel drive car with doors on it, and an available hard roof. Contrary to conventional car and truck chassis, it used a sturdier fully box-welded frame. Furthermore, due to post-war steel shortage, and aluminium surplus, Land Rovers received non-rusting aluminium alloy bodies, favouring their longevity. In 1992, Land Rover claimed that 70% of all the vehicles they had built were still in use.