Chair Arm Pads Caps Replacement Armrest. Listing is for 1 set (2pcs) of brand new armrest pads for use as replacements for most styles of fixed T-Arms or adjustable arms used in the office chair industry. These arm pads are harder than most on the market. They are made of very dense PU foam material and are intended to last a while. So if you are tired of your pads getting cracked and worn out in a short time, these are the pads for you.