Lomart liners are produced using a special blend of natural, raw materials that insure top-quality vinyl for all liners. 20 mil variable depth liners for depths up to 6 1/2 feet feature an additional surface area of rugged sidewall vinyl for maximum depth coverage and is designed to allow for an Optional Special-Purpose Deep Swimming Are for Underwater Swimming Only. No Diving. No Jumping. The Sunset Cove Full Print Premium Variable Depth Liner is a beautiful water reflection design on the sidewall and pool bottom which will add luster to any pool. 20 year warranty.