Startech Ergonomic Anti-fatigue Mat For Standing STSMAT, Black, Anti-fatigue mat is made of premium polyurethane foam, Comfort and durability. Work more comfortably at your standing desk or sit-stand workstation, with this anti-fatigue mat. It offers a durable cushioned surface to stand on throughout your workday, and it’s conveniently sized to tuck under your desk when you’re not using it.