Attaches to the Industrial Hot Knife. The included 12" blade can be used to make any shape groove. The Sled keeps the depth of the groove consistent. Simply pin a straightedge, or any other template to the foam and run the edge of the sled along it. The 12" blade is super stiff and will not lose its shape when used to cut any density foam. Great for making grooves for wiring and plumbing in EPS insulation foam, for crown molding, and more.