The new Obus Ultra Forme Backrest is specially designed and scientifically proven to relieve even chronic back pain. By shifting the spine into a positive neutral curve, the Obus Ultra Forme™ Backrest's innovative design relieves pressure on the lumbar discs and lower back muscles. This in turn reduces muscle contraction by an amazing 50%, dramatically alleviating much of the strain typically felt in these muscles.Experience the Obus Ultra Forme Backrest - the latest technological advance in back pain management from Obus Forme.For optimal results, use the Obus Ultra Forme Backrest and Obus Ultra Forme Seat together. They create a complete, comfortable and ergonomic sitting experience by:Encouraging proper alignment between the pelvis and spineAssisting in ciruclation through the lower extremitiesFurther reducing pressure in the back MEDIUM - For people 5'2" - 6'2" (1.57m-1.88m) Tall Important shipping note: due to the size of this product, we are unable to ship using Xpresspost--we will automatically ship this product using regular parcel post regardless of the shipping method selected at checkout. Contact us if you have questions.