Amazon.com : Large Pond Liner for Outdoor Ponds - 20ft/16ft/13ft/10ft/6ft/3ft W, 19.6 Mil Thick Lotus & Fish Pond Liners, Black HDPE, Rectangular (Size : 3Mx7M(10ftx23ft)) : Patio, Lawn & Garden
VEVOR Pond Liner 13 ft. x 20 ft. 20 Mil Thickness High Tensile Tear-Proof Flexible HDPE Pond Skins for Artificial Lake, Black FS-1320T0.5MMHBQ6V0 - The Home Depot
Fish Pond Liner Garden Pool HDPE Membrane Reinforced Multiple sizes 200G/SM | eBay