DuPont Tyvek HomeWrap is a nonwoven, nonperforated sheet made by spinning extremely fine continuous high-density polyethylene (HDPE) fibers that are fused together to form a strong uniform web. DuPont Tyvek is a unique brand and the only product manufactured this way. This tough, durable, and unique structure is not susceptible to the compromises of a perforated material. The fibrous structure is engineered to create millions of extremely small pores that resist bulk water and air penetration while allowing moisture vapor to pass through. DuPont Tyvek Home Wrap achieves the ultimate balance of weather resistance and vapor permeability. 1200 seconds of Air Resistance.