Kimtech™ Pure W4 Critical Task Dry Wipers have a 100% polypropylene construction and are thermally bonded with no glues or binders. They are acid-, base- and solvent-resistant and feature straight, clean knife-cut edges to minimize lint. The wipers are double bagged with a case liner and are specifically designed for ISO Class 4 and higher cleanrooms. These wipers are ideal for use in the pharmaceutical, high tech, biotechnology and medical device industries. Additionally, the polypropylene used in the manufacture of Kimtech™ Pure W4 Dry Wipers meets the requirements set forth by the FDA for Olefin polymers (21 CFR 177.1520) used for food packaging/contact. (Please note, the FDA does not regulate wipers as food packaging).