Peter Opsvik is a Norwegian industrial designer best known for his innovative and ergonomic chairs, and the father of Jazz bass player Eivind Opsvik. Opsvik's furniture can be found under the brand names: Rybo (Garden), Nomi High Chair, Håg (Capisco, H04, H05, Conventio Wing), Varier, Stokke (Tripp Trapp) Naturellement (Reflex), Cylindra (Furniture objects) and Moment (Globe). His book Rethinking Sitting came out in 2009 giving insight into his thinking about sitting and explaining the philosophy behind his chairs. Peter Opsvik is also a jazz musician. He has been a member of Christiania Jazz band from 1972 and the band Christiania 12 from 1993. Essential concepts His probably best known work is the adjustable Tripp Trapp (1972) chair for children, the first chair that "grows" with the child from toddler to teenager. It is manufactured by the company Stokke and has sold in more than seven million copies. In 2013, together with Evomove.com, he launched the Nomi high chair concept. The saddle chair Håg Capisco was launched in the 1980s and inspired by the horseback rider's dynamic posture. The goal, however, was to create a sitting device or work chair that would invite the user to assume the greatest number of sitting postures possible. In 2010 this design classic was made accessible for a wider audience when the Capisco Puls was launched. A balancing tilt is highly advantageous since the user automatically controls the tilting movements of the chair without having to think about it. The user can concentrate on his/her activities and does not have to bother with mechanical regulation of the chair. The chair follows the natural inclinations of the body and automatically stabilises at the body's selected sitting angles or at the angles that are required by the work task being done. The simplest way of verifying this is to try out one of his chairs in front of a work table during a normal working day. The chair tilts forward when the user want to be active at the table and tilts backwards if the user wants to relax or talk on the telephone. Often such variations occur many times per minute. Hans Chr. Mengshoel initiated the concept of kneeling chair posture in Norway, and Peter Opsvik was one of three designers who developed chairs based on this principle that all had Balans in their names. The others were Oddvin Rykken, and prof. Svein Gusrud. Peter Opsvik's