This is a plastic mat to protect the living room carpet and help the chair roll more smoothly. To me the key was price which at [$] could simply not be beat.
Would not buy again and thinking about returning the mats. They are not thick enough and I am using them on very short pile commercial carpet. The chair is leaving permanent dents in the plastic when I sit on it and I am not overweight whatsoever. My old mats that were replaced by these were in better shape after 10 years than this new set only being 10 days old.