ALLEX Insulation Knife with Sheath 8" Long Cut, Japanese Stainless Steel, Insulation & Styrofoam Cutter with Blade Case, Serrated Sharp Duct Knife Tool, Made in JAPAN

Very useful. It cuts like a razor though so be careful with it.

Cuts like butter for r38 fiberglass and r30 fiberglass r19 faced fiberglass

If you are not using this you're making a mistake. This is the best way to cut mineral wool and other insulation. Doing a van conversion, I used it on mineral wool, fiberglass, and thinsulate. Highly recommended. I understand it also makes a great bread knife, but I never used it in that application.

The knife is nothing special. It’s just a kitchen knife that is serrated.

I use this to cut off spray foam in areas where my reciprocal blade couldn't reach. The blade itself is very flexible and allows you to cut with precision.The project of over, however the blade is still sharp, getting a lot of beating

I had a lot of foam boards to cut through. This thing was the most effective tool i tried, and mostly didn't make me want to pull a van gogh while working with styrofoam.

Sharp knife and the extra length was perfect for cutting 4" mattress foam.

Never again