3/8" x 4 1/2" top x 5 1/4" bottom Foam Roadbed.  This auction is for 10 pieces 48" long (40' total), black in color. This roadbed is very dense foam, much firmer than the Woodland Scenics foam, and has great sound deadening qualities. A great substitute for Homasote or cork. I can custom cut widths in this material for different scales or yard mats. Please ask questions before you buy.. I will send you a sample, just email me with your name and address thru the ask a question option....