SmartLine® Sunlight Overlap Above Ground Swimming Pool Liner – 25 Gauge (Choose Size). Whether installing for the first time or replacing an existing liner, our liner offers durability while not breaking the bank. Pool height is determined by measuring the outside wall from the ground to underneath the top rail. Material: 100% Virgin Vinyl. Overlap Connection – This type is the most common and simply folds over the corrugated metal wall and drapes down on the outside of the wall. The liner is held in place by plastic coping strips. You may wish to replace these if your old ones are brittle and dry. Features of the Liner. High-temperature curing, computer-controlled process insures that 100% of the material is “Vulcanized” to the highest possible tolerances. Vacuum Sealed, high-volume air pumps combined with electronic air filters remove all impurities before bonding. High-pressure heat bonding, computer balanced combination of high pressure and exact temperatures insures a void-free permanent bond. The most technically advanced radio frequency vinyl welding reduces the chance of cold spots in the seaming process. Hand-folded flat, to reduce wrinkles automated packers twist and force the liner into the box which can cause permanent creasing. Most Common Types of Liners. Overlap: This type is the most common and simply folds over the corrugated metal wall and drapes down on the outside of the wall. Please make sure you measure your swimming pool twice before purchasing. Lastly, none of our liners will fit Intex, Coleman, Bestway, or any soft-sided swimming pool.