Klöber Matthias Dohm Seating Office chairs 5-star base on castors Seat upholstered Lumbar support height adjustable Armrests pivot in-or-out adjustable Armrests front-to-back adjustable Armrests side-to-side adjustable Armrests height adjustable Backrest tilt adjustment Seat height adjustment Synchronized tilt mechanism Certification DIN 1335 part 1-3 Certification mark ergonomic Certification GS Metal Aluminium Base metal Contract Office