This organizer is about 8-3/4" x 5-1/4" x 5-1/4" and has five compartments! And YES! this file is compatible with both the 12x12 and 8-1/2x12 mat, really! This file comes with the base tray, back row divider boxes (cut three), one long front row divider box, and one small front row divider box and the boxes are very generous making this perfect for holding all your must-have's on your desk...and just think of the gift-giving possibilities you could create with this one!

http://jamielanedesigns.blogspot.com/2013/08/large-desk-organizer.html