mat completely stained entire width at foot with black substance. Have not yet cleaned off but it looks terrible. Good thing it's on top of mat and not bottom which may well have discolored carpet!. This is the third mat I've purchased from you over the years and I'm not happy with what was sent.
Good to allow desk chairs to roll easily and save carpet wear if you’re in a carpeted room. If it appears warped when originally purchased or delivered, allow it to flatten out in a warm area for up to a day or two before using.