The SUB-0 SoftCell Gel & Memory Foam Select Pillow is a unique construction of individual pockets of the softest poly fibers on one side reversing to a somewhat firmer side featuring a memory foam insert covered with our cooling gel layer. The base of the top side contains a special supportive neck bolster for added neck & back support. Another small poly pouch is included to further adjust the pillow from soft to medium to firm support for stomach, side & back sleepers. Remove one or two layers - reverse them if you please and you can customize to your desired firmness. The cover is of our own FRIO fibers for a rapid chill if needed and a Tencel® blend for a dry temperature sensitive effect. This may be the last pillow you will ever purchase!