Gorilla Floor Padding for Above Ground Swimming Pools Size: 21 Foot Round (NL124) Gorilla Floor Padding Cut to Your Above Ground Pools Size Sits Underneath Your Pool Liner for Added Cushioning and Extra Liner Protection  Extends the Lifetime and Safety of Your Liner and Pool / Cushioning Eliminates Footprints from Forming Extremely Hard to Penetrate - Specially Designed Geotextile / Strong Felt-Like Material Approximately 1/8 Thick Impervious to Cuts from Sharp Objects, such as Glass, Roots and Rocks, Virtually Eliminating Vinyl Liner Bottom Leaks! Padding is Cut to Size and Seamed to Your Above Ground Pool- No More Cutting and Taping as with Foam!