With a full 1.5-inches of foam, FlexMat Plus is the thickest, most-comfortable closed-cell mat available. It is highly versatile for stand-alone use and will increase warmth and puncture protection for inflatable mats.When layered underneath, FlexMat Pluss R-value of 2.8 can boost a 3-season sleeping mat to 4-season efficiency. The folding form is quick to deploy and ensures a tidy load when attached to a backpack, bike or kayak.