I ordered the 10M. It works well, seals well and looks neat. My primary concern was condensation and heat in my metal building. I give it 5 stars on improving my building on both of those things. I previously had fiberglass in the building but it started cracking so I certainly wasn't going to replace it with more fiberglass. I was in a hurry. Fortunately, Prodex Insulation4less shipped quick.