SHISH all-weather tank guard the best protection for overhead plastic water storage tanks Shish all-weather tank guards reflect 97% of the sun's heat radiation and help retain water temperature during summer and winter. Water tank insulation also stops the degeneration of the plastic tank by protecting it from the sun's rays, thereby increasing its life. Shish all-weather tank guards easily fit on existing vertical and horizontal tanks and are easy to install using the installation kit and the instructions provided.