Oatey 5 ft. x 6 ft. Gray PVC Shower Pan Liner 41630 - The Home Depot
Amazon.com: SINGFORM 40 mil Thickness 6' x 8' Shower Pan Liner | PVC Waterproofing Membrane Shower Pan & Base Sheet for Bathroom and Kitchen, Utra Durable, Grey : Tools & Home Improvement
Composeal Blue Vinyl Shower Pan Liner Waterproofing Membrane Complete KIT | eBay