Latham DXLG00S2040-19 20' x 37' 10" x 40' 4" Lagoon In-Ground Pool Sub-Assembly Opt 1. Polymer pool walls manufactured by Latham are 100% corrosion-free, offering unmatched durability and resilience. When installed properly, polymer walls stand up to the test of time, weathering decades of even the brightest sunshine and rowdiest splashing. Not only is polymer tough and rugged; its anti-corrosive properties also make it ideal for saltwater pools, which are increasingly popular due to their easy maintenance.