BK19A008X028 Blokburst - Natural Wonder Stair Tread Set (13) Stair Tread 50% Polyester/30% Polypropylene/20% Cotton - Stair Tread. Bold & Fun! Colorful braided stair treads made of soft chenille blended with a hint of colored fabric is the perfect accent for any staircase needing color. Soft Chenille Texture: Chenille yarn makes the braids soft and plush to the touch. Reversible: This rug is crafted to last and last. Reversibility adds longevity with twice the wear and tear.