Tu-Tuf #4 9' X 100' Vapor Barrier Tu-Tuf #4 is white with a smooth texture while the XF version is translucent with a slightly ribbed texture. * Vapor Permeance: 0.00741 * Water Resistance: 100 dry indicator/hour * Tensile Strength: 8507 psi 34 lbs. per inch width * Puncture Resistance: 275.8 beach units (6 times more puncture resistant than 3-mil poly) * Manufacturer: Sto-Cote Products