Pond Liner 20 x 25 ft | 45 Mil Thick EPDM Material | Flexible Black Pond Skins for Fish, Koi Ponds, Waterfalls, Water Features, Fountains & Water GardensSpecifications Place of Origin China Main Color Black Main Material Rubber Dangerous Goods #dangerFlag# Dimensions & Weights Assembled Length (in.) 30. 31 Assembled Width (in.) 23. 82 Assembled Height (in.) 12. 60 Weight (lbs) 134. 22 Product Features Keep Your Fish Safe: By using a pond liner, you can prevent water and soil from seeping out of the pond and contaminating water resources. This will create a better living environment for your fish.