The Brownmed IMAK Ergo Back Cushion is made of high-quality foam that helps users maintain a correct posture. Its air pocket design invigorates the back muscles and helps improve blood circulation. This back cushion fits most chairs and car seats. The IMAK Back Cushion and Lumbar Support offers superior comfort and lumbar support for your car or office chair. Unique design hugs your lower back to help improve your posture and reduce stress to the back. Features large and small vacuum-formed air pockets which provide a "pressure point massage" to your back. Air pocket design helps stimulate blood circulation and invigorate back muscles. Air pockets allow air to circulate to keep the back cool and comfortable.