Poly Lining Systems PLS 1776 is specially formulated and promoted for use in the PLS 1776 Double Wall Tank Bottom Lining System specifically designed for above ground bulk petroleum storage tanks. The PLS 1776 System consists of PLS 1776a Base Resin, PLS 1776b Structural Reinforcement Fiberglass, PLS 1776c Velvet and the PLS 1776d Interstice Assembly.