This is cross-linked foam sheeting. It is light-weight and extremely durable. Two of these are enough foam to build a flatblade short sword. Ordering multiple pieces will result in an un-cut roll of foam.
The sheets come in three different size/density options:
The .5"x8"x18" sheets come in 2# and 4# densities.
The 1"x18"x24" sheets come in 2# only.