(Half stack which includes two blocks of each size as well as individual blocks are also available; please see listings for CB-205, CB-212, CB-224 & CB-248). The Original & Grand Canyon Bar Blocks feature a combination of crosslink polyethylene/100 ILD polyurethane foam filler, ultra-durable 18 oz. covers and 4" wide hook and loop fasteners. Available in royal blue, red or green.