In many European international locations, this chair is licensed as a medical gadget. Nowadays, SpinaliS is successfully promoting its chairs all over the world and helping folks with dangerous backs to sit down with out ache. SpinaliS chairs hold a worldwide patent for a unique active sitting know-how and have helped over 100,000 prospects. Most of the office chairs manufacturers create office chairs with fastened seats. These forms of chairs for static sitting will sooner or later trigger your again pain. A typical backrest is between 12 and 19 inches extensive.