CTI’s SCR645 Series Shoe Covers are manufactured with the same outstanding quality as all of our other Scientific Division products. They are strong and durable, but made from a lightweight material that offers breathability and comfort. All items are individually inspected for quality and workmanship. The SCR645XL-150 is compatible with class 100 environments and excellent at containing moisture and dirt, while repelling external moisture and oil. The compressed Polyethylene fabric called PP/PE has excellent resistance to chemical corrosion and solvents, is non-toxic, odorless, and heavily textured for sure grip. (300 per CS )