Pocket springs with 3D Gusset and an outer layer of viscoelastic /Memory foam. Effective for “learning and remembering” the exact shape of your head and neck, adjusting continuously to any position during sleep. Pocket Spring with 3D Gusset for 20% more airflow. The 3D gusset promotes better airflow, allowing heat and moisture to escape easily keeping you cool and comfortable through the night. It relieves pressure on sensitive areas of the head and neck, so the muscles are relaxed and blood flow is more free. It optimizes the head/neck alignment with the spine, increasing comfort and overall feeling of well-being.