[Crex]

Goes on like watery paint with grit. Very thin coat, acts as a reflector to re-radiate heat back into center of forge.
Which in turn improves fuel efficiency on some forges. Will depend on forge interior design as to whether it's really worth the effort/expense....blown forges and large volume forges not so much help as Ray indicated.
Works quite well in smaller horizontal venturi burner forges. Not tough at all, but most use satanite type furnace cement as rigidizer for protecting and holding K-wool in place providing a base for ITC application.
It's pricey, but can be reconstituted if it drys out and a little goes a very long way. I use it on all my forges and can see a big difference in fuel burn efficiency.....again relative to forge/torch design. Not trying to sell the product, just what works for me.