Exceptional Cask Selection Mark XI A blend of 12-year-old rums from Foursquare distillery in Barbados, matured in ex-bourbon and ex-Madeira casks. This single traditional blended rum (a blend of pot- and column-distilled rums from the same distillery) is part of the wildly – and deservedly – popular Exceptional Cask Selection series, which also includes notable bottles such as Foursquare 2005, Dominus, and Empery.