Polyex Pond Liner 16' 4'' X 11' 1'' Koi Fish Pond Garden Liner 16'4" x 11'4" (5mx3.5m) Guaranteed for 25 years against faulty manufacture when installed with Permalay or Polyfibrelay underlay Reversible Black or Brown Finish Liner thickness is 0.030mm, 12 mil UV stabilized on both sides for long life