Dynaduck fabric, with 10.10 oz army duck cotton canvas and a water repellent, mold and Uv resistant finish. Double-stitched seams with reinforced corners for added strength. Heavy-duty frame with anodized aluminum poles. Proprietary shock-absorbing bungee cords to stand up to harsh weather conditions. Pre-installed heat resistant silicone-coated stove jack with a 5 and 6-inch pre-cut pattern.