3 Feet Wide x 10 Feet Long Flat Sheet Pond Liner in 20-mil Black PVC. ** THIS LISTING IS FOR A FLAT SHEET POND LINER.** What does that mean? That means that the liner is made from a flexible material that is designed to be draped into your pond, tucking and folding it into position. IMPORTANT - You need to account for your ponds width, length and depth when choosing the correct liner. Measure your pond by adding the following: Overlap + Depth + Width + Depth + Overlap to find the absolute minimum liner width you require and then repeat the process for the length of your pond. Tip - Be sure to order a liner at least slightly larger than you calculate (you can always retain the extra for future use). Note - All of our liners are made-to-order and most sizes do require us to weld multiple panels together but rest assured, our Quality Team checks every weld before we package the finished product. As with all of our products, these pond liners are proudly made in the USA!