I don't know what it is but I can't sit in the chair for more than 2 hours before my rear hurts. The back is great and I like the headrest but I just can't keep it.
Sturdy chair - larger than I was expecting. Very comfortable with easy “pull up push down” lumbar support comfortable headrest back tension adjustable arms raise up or lower very easily and are “cushy”. So easy to put together - literally took longer to unpack everything! Only included Allen wrench needed for assembly. Love this!
This chair is worth every penny. Got it on sale at my local store and the putting together took me maybe tops 10 minutes. It's comfortable the mesh prevents sweating the head rest is amazing; something you don't think you need until you have it. I work from home much better now no back nor neck pain. I highly recommend this chair to anyone.