DIAMOND DOTTED FILM is made of electrical insulating paper with diamond-shape epoxy resin dotted in both sides. The epoxy resin used in D.D.P. contains a kind of incubative hardener material, it is a dry and crisp material at normal temperature use in Good dielectric properties and mechanical properties after being heat-solidification. As interturn insulation for coils of oil-immersed transformers Interlayer insulation