Delta Cooling Towers are made from a Corrosion Proof engineered plastic, totally Seamless and are Low Maintenance by design. The cooling tower shell will never rust, flake, chip, peel or ever need painting or protective coatings applied. Introducing our New Anti-Microbial Cooling Tower Shell with Anti-Microbial HDPE resin, which is fully compounded throughout and withstands most aggressive chemical treatments.