Simplicity is key. Compression has the amazing ability to provide pain relief for countless conditions that can be found all over the body. The basic principle of compression is what any A4466 orthosis is based on. An A4466 billing code is assigned to any type of garment that is made of elastic or some other similar material. Whether it is a belt, sleeve, wrap or some other type of covering so long as it is stretchable, and has a medical purpose it qualifies as an A4466.