Friso Kramer industrial chair for Ahrend ca 1960

Rare work chair / adjustable drawing chair (drawing table chair) designed by friso kramer for ahrend de cirkel in the 1960s. See the photos for more details! The height is adjustable with a rotating button of about 57 to 73 cm. The folder can be set separately with another rotating button. The chair has the original ring/footrest. The frame is made of iron and the seat/back is made of birch wood. The chair is in very good condition.