20 Year Limited Manufacturers Warranty 45 Mil (1.14 mm) (0.045") EPDM 75 Year Lift Expectancy Environmentally friendly SAFE for fish and plant life Pondliner is the foundation of every great pond and specially formulated for water gardens. Don't settle for anything but the best. Firestone Pondgard pond liner is fish safe, strong and durable yet pliable and will last you for many, many years. EPDM 45 mil is the #1 choice for contractors, landscapers and consumers that demand only the best.