Bentley Mulsanne Key Celebrates Its Centenary Mulliner, Bentley's custom coachbuilding unit, has designed a distinctive keycase to commemorate the 100th anniversary of Bentley. It is made from Dark Stained Burr Walnut with Piano Black Veneer and includes a fluttering "B" paperweight, keys, and an album of never-before-seen 1930s 8 Litre