The Sea to Summit Camp Mat Self Inflating is a self-inflating sleeping mat with 1.5" of foam thickness with Delta Core-V coring to remove unnecessary weight and minimize packed size. A 75D polyester top and bottom fabric offer durability. R4 insulation rating for 3-season sleeping. Features:Smaller die-cut holes in body contact areas -- shoulder, hips, and feet -- keep you warm Larger die-cut holes in non-body contact areas reduce the mat's weight and bulk Constructed using Delta Core-V techniques to minimize weight and bulk, yet maximize warmth. Using pressure-mapping data to define the contact areas creates a map for the distinct core pattern. Patent-pending multi-functional valve. High flow rate for easy inflation; one-way deflation mode prevents re-inflating while packing up and fine-tuning bleed valve for customized comfort Robust and durable 75D polyester with extrusion laminated TPU used on top and bas