The liner is as described. I used a double layer over a pad over 6 mil visqueen since this pond is in a hole carved out of volcanic rock (very sharp edges, although I ground most of them down). I do not forsee and leaks due to punctures! It was necessary to spread it out in the sun for a few hours to get out the wrinkles. My sole complaint was the exorbitant shipping fee just because we live in Hawai'i. A $100 flat fee, rather than actual shipping costs, was charged. Free shipping only applies to the contiguous 48 States. You don't see the fee until you go to check out. The product is great.