Chair Caster felt holder

I have hardwood floor, and my office chair with caster wheels is not so good for this floor. I used to have a small rug just so that chair can sit in one place. Instead I designed a small felt holder caster cup which can slide into the place of the wheel. It has edges which fit inside the end of each leg. You need to print 5 of these, and they fit snug. Then cut a piece of felt (you can buy large 4"x4" felt pads at HomeDepot) and stick underside. Now the chair sits safely on the hardwood without