U-fo Mogul Seat Cushions Set (Lumbar Pad & Seat Pad). Fits “Size C” of Herman Miller Aeron Chair. The Mogul lumbar and seat pad is a back and leg support system designed to improve ergonomics and comfort on the Aeron chair. It is made with varying high-density foams specifically designed to complement and upgrade the Aeron. Mogul comes in a variety of leathers and materials. Is attached via a magnetic strap and will not harm the back surface of the chair. We use a hybrid of molded HR foam and sheet foam. It’s roughly 2 thick, but on the softer side. If even more lumbar support is desired our large soft lumbar works well with the standard plastic like unit from Herman Miller that slides down the back of the chair. If you have the Posture-Fit installed on your chair you can use our Lumbar with it by loosening the Poster-Fit so our magnetic strap can slide beneath. Once you’ve found your desired location you can tighten your Posture-Fit as you like. You don’t need to have a pre-existing Lumbar unit on the chair for ours to work. Gently slide our unit to your desired position anywhere. Have plastic clips that slip behind the seat and clip onto the underside of the chair to help keep it from shifting during normal use. Our seat is roughly 1.75 thick under your. Ischial Tuberosity rear end. All of the Seats and Lumbar Units have the same construction with the exception of the top surface. The Bull is the thickest and may add a little firmness or support. The Diamond Pleat is the Softest of the grouping. Is just that, 100% bull hides. It is matte in color and soft, but not smooth. The thick leather with its heavy veggie retannage keeps the edges looking great and the seat area will conform to your body’s curves.