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

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.

Great knife for cutting polyurethane foam for a gun case. Previously tried using a hobby knife and thought I'd give this a try - Japanese are well known for the quality and genius of their hand tools. Works perfectly with the fine serrations using a controlled sawing motion. Some challenges with navigating tight turns but definitely better than the hobby knife. Won't buy again because it works so well and I don't need another...

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.

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

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

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

Worked good for cutting insulation for the first two rolls. Started getting dull. Had to go back to using scissors.

Never again