All units are named for the closest nominal effective working area that the unit creates. A 48x48 unit can legitimately plane down a 48x48 inch slab A 48x96 unit can legitimately plane down a 48x96 inch slab, with the length capacity being undersold since it can handle 102 inches of material. A 22x96 and a 48x72 unit are identical in component make-up, the only thing that changes are how the rails are arranged. All rails are the same design; therefore, you can expand both the length of the units as well as the width of the units 72 inches wide is the widest capacity unit we will sell. This is made by joining a 55-inch rail to a 27-1/2-inch rail for a total rail length of 82-1/2 inches, which is honestly a massive span. See notes below regarding deflection.