First, I am also one of the duo back seat offers you permanently exceptionally high degree of comfort. This split backrest, two elements which can move independently flexible, this patented and ergonomic for years successfully established principle standards. The back muscles are supported and unhealthy pressure is avoided in the back. Do you feel much more comfortable and healthier to sit. Proven relief of measured duo back the disc by 50%, according to reports from universities, professors and doctors. The technical data of the duo back DB 11 / DB 12 office chairs, the distinction between DB 11 and DB 12 office chair office chair, the backrest, which has in the DB 12 a covered with fabric back and a slightly different form. In the DB 11 is the back of a plastic cover. Office chair / office chair, Grahl, duo-back office chair, DB 11 * backrest with height and width-mounted * Flexible back parts: * db 11 withblack plastic cap, 43 cm high * 12 db on both sides padded, 43 cm high * ergolast synchronous mechanism with contact pressure control * sliding seat, pneumatic vertical spring Sitzneigevoreinstellung * * Polished aluminum star base 650 mm, black, or * no tools wide and height adjustable armrests with adjustable low-and-tilt The office chair PU conditions DB 11 / DB 12 is equipped with a synchronous mechanism in which money is the inclination of the back seat of 1:2,9. That means always in the back of this money goes along the seat. The Duo-back back can be adjusted by a mechanism in the width and height. The seat depth adjustment can be operated via Knopfduck too. The Grahl Ergolast ensures optimum adaptation to the weight of the users and easily with the right hand to operate. Optionally, it is still mounting a headrest. Another Opiton is Viskoschaum of a recommendation for prolonged sitting is!