Hz series cover is a good electrical insulation seal waterproof safety protection products. The utility model has the advantages of convenient installation, excellent environmental adaptability, long service life, etc. . The utility model is mainly used for insulation protection at the connections of power transformer terminal and other wiring equipment. To prevent short-circuit accident caused by foreign body lapping animals climbing down, to prevent electric shock, pollution and condensation flash phenomenon, reduce the air and harmful gas corrosion of conductive materials, extend the use of electrical equipment life.