Another characteristic of these early office chairs were their fixed seat to backs. They are like a static desk chair whose legs have been swapped for a castor base. Later chairs introduced an adjustable back rest that permitted the user to adapt the chair to their own stature. Backrests can be moved up and down, or forward and back relative to the seat allowing the office worker to tune the support of the chair.
The introduction of the adjustable back begins to reveal the familiar form of the two-pad adjustable chair format that has carried on to today's modern task seating.