Sinus is a modern classic from 1976 which was already ahead of its time when it was first launched. With rocking spring steel skids whose shape give the chair its name, as well as unusual upholstery. The round seat and back upholstery elements are held in place by leather straps. Sinus appears to be weightless as it rocks lightly. And anyone who has come to rest on the distinctive upholstery will never want to give up this favorite chair again.