Office Master AF428 is an "Executive Synchro" chair with 5-lockout positions (based on AF528).
The Affirm Series' contemporary mesh back design has been so appealing partly because of its rectilinear outline and range of mesh-related options. But now we’ve added another exciting backrest option: A fully cushioned, fully upholstered rectilinear high-back option that can be used with any of the existing Affirm mechanisms. Simply order as an AF4x8, where the x indicates the mechanism style (i.e., ‘0’, ‘1’, ‘2’, ‘7’,’8’).
One of the salient features of this chair is its synchronous tilt mechanism. This mechanism reduces the seat rise when you lean back in the chair. This means, that when the back is reclined 2 inches, the seat is raised by only 1 inch. This gives a 2:1 back to seat ratio. So with the synchronous tilt mechanism, the movement of the backrest is larger than the movement of the seat. With the standard swivel-tilt mechanism, the back and the seat are fixed together, so when you lean back the seat is raised at the same rate the back is being reclined. When this happens, the back is reclined 2 inches, and the seat is raised 2 inches. This give a 1:1 back to seat ratio.
With synchronous tilt mechanism, you have the ability to rock in the chair, while keeping your feet on the ground. With standard swivel-tilt mechanism, when you lean all the way back in the chair, you can prop your feet on the desk or ottoman!