The 360 photo mode shows that the chair has locking hinges on both side of the chair. But only one size has that lock, the other moves freely and the backrest twists to the side that does not lock. That is the hinge that several people have said failed or broke.
The Photos are wrong
The 360 photo mode shows that the chair has locking hinges on both side of the chair. But only one size has that lock, the other moves freely and the backrest twists to the side that does not lock. That is the hinge that several people have said failed or broke.