Zoned Pin-Core Technology The two biggest complaints against memory foam are its heat retention and firmness. We fixed this problem through zoned pin-core technology. The pin-cores optimize air circulation, and the differing sizes of holes were created for best head and neck support. Large holes for great head support, and smaller holes for proper neck alignment that will make the pillow feel more plush.Hypoallergenic Cover Covering this pillow is the cotton velour cover. This cover is breathable, hypoallergenic, and easy to remove for laundering in order to keep a healthy sleeping environment.