|Meets or exceeds the specifications of ASTM D-4551, which specifically covers vinyl shower pan liner. |Is manufactured from 100% Virgin Poly Vinyl Chloride Resin. |Treated with biocides which prevent the growth of mold, mildew or fungus. |Is unaffected by concrete or cement. |The product maintains its integrity when installed in a damp, moist environment (the typical shower pan) away from the effects of sunlight and ozone. Under no circumstances should PASCO Vinyl Shower Pan Liner be used where there is direct exposure to the elements.