The chassis is a carbon-fibre monocoque with some tubular elements. The chassis is a carbon-fibre-reinforced plastic monocoque and the brakes used are electromechanical brakes. The chassis is a carbon fiber monocoque with a steel roll cage, all by Dallara. The tub has been redesigned and incorporates an aluminium monocoque structure for increased rigidity. The revolutionary frame is an advanced aerofoil cross-section using a carbon composite monocoque. The F1 was one of the first production cars to use a carbon-fibre monocoque chassis. The term monocoque is frequently misapplied to unibody cars. In 1981, McLaren had built the first car monocoque from carbon fibre composite. Triumph Rocket III engines, enclosed in a carbon Kevlar monocoque. The Toyota Sera is a 3-door hatchback coupe of monocoque steel construction. The later three-seat 47H had an enclosed cabin with full cowling and monocoque tail boom. Another type of carbon fiber frames are manufactured in a single piece, called monocoque construction. The car was also Brabham's first fully composite monocoque. The ascendancy of monocoque construction also made the pillarless design less practical. Modern monocoque designs include a virtual keel.