SilverBack® brand vapor barrier was made for one purpose, to offer the most durable choice in a  crawl space vapor barrier. While others claim to measure 20 Mil, the SilverBack® actually does. Offered in both Cord Reinforced (SR) and High Strength (HS) you will find our 20 Mil really is 20 Mil. SilverBack® vapor barriers are not measured at the string, but rather where it counts most, the plastic.  Match SilverBack® vapor barriers with top quality seam tape and a dehumidifier to get the most out of your encapsulation project.