Rare Thonet swivel (desk) chair, 1st half 20th century, Austria

Beautiful and not so easy to find model (desk) chair by Thonet, Austria, first half 20th century. Adjustable in height with lowest seating height of approx. 46 cm, highest 61 cm Width total 57 cm D total 57 cm Great patina, solid condition. Some signs of ageing as shown on images.