FREIVID Anti-fatigue mat, Diseröd gray-green If you usually stand at a desk, then this mat can come to the rescue. Filled with foam that relieves pressure on the knees and back, and with a washable cover that has anti-slip material on the underside. Anti-slip material on the underside.. FREIVID Anti-fatigue mat - Diseröd gray-green. Perfect for those who stand for long periods at their desks since the mat's high-density foam relieves pressure on the feet, knees and back. The dense, elastic foam filling quickly regains its shape after use. Anti-slip material on the underside.