The new XWB fuselage has a constant width from door 1 to door 4, unlike previous Airbus aircraft, to provide maximum usable volume. The double-lobe (ovoid) fuselage cross-section will have a maximum outer diameter of 5.97 m (19.6 ft), compared to 5.64 m (18.5 ft) for the A330/A340. The cabin's internal diameter will be 5.61 m (18.4 ft) wide at armrest level compared with 5.49 m (18.0 ft) of the Boeing 787 and 5.86 m (19.2 ft) of the Boeing 777. It allows eight-abreast 2–4–2 arrangement in premium economy layout, with the seats being 49.5 cm (19.5 in) wide between 5 cm (2.0 in) wide arm rests. Airbus says that the seat width will be 1.3 cm (0.5 in) greater than a 787 seat in the equivalent configuration. In the nine-abreast, 3–3–3 standard layout, the XWB's seat width will be 45 cm (18 in) which will be 1.3 cm (0.5 in) wider than the proposed equivalent seat layout for the Boeing 787. A ten-abreast high-density configuration is also available.