In these days of insulated air mattresses & clever technologies the classic Ridge Rest offers a simple & hugely reliable alternative to those looking for a comfortable nights sleep with minimum fuss. This closed cell foam mat has been designed with ridges that trap air between you & the mat & the mat & the ground helping to create an R-Value of 2.6, which in real terms relates to 2/3 season performance, so it is not suitable for use on snow or frozen ground. R-Values are an international standard of insulation & (in simple terms) indicate the materials ability to reduce heat flow through conduction, radiation or convection. Therefore the higher the R-value, the lower the heat transfer & the greater the insulation properties of the material. Slide this Ridge Rest under a lightweight air mattress to boost performance & also to add a layer of protection against punctures. Closed cell foam material Ridges to trap air Lightweight Extremely durable