Applications that needs to work in contact with water needs an insulation that remains relatively unaffected. Water resistant film is exclusively used for such applications like windings of stirrer coils (EMS coils). Polyimide film with FEP lamination on one or two sides are wrapped and heat bonded with high frequency induction heating followed by radiant heating makes a sheathing with high dielectric strength when tested immersed in water. The wire is also covered with one or two layers of fiberglass and bonded with varnish for better windability and coil forming capability. Glass covering offers better mechanical property to insulation. Insulation thickness can range from 0.23 mm to 0.50 mm depending on number of layers of Polyimide film applied and glass covering.