Review on Everhard Extra Long Insulation Knife with 5-inch Blade - Model MK46300 by Christopher Holker

Attached video shows the knife in action on 2.5 inch felt coated poly insulation. I've also tried straightening the knife instead of using it like a saw, but that's an alternate method. It takes about 4 passes before it all goes through. This method also leaves a lot of dirt that needs to be removed if the knife gets stuck and tears through the insulation instead of severing it. Foam board and is better than a drywall cutter, but to cut hundreds of foam boards you need another, more efficient method.