APPLICATION Suitable for indoor and outdoor electric, communication, fire fighting apparatus, iron and steel smelting, petrochemical industry, electron, power system,railway, building, mine, air and sea port, hotel, ship, works, waste water treatment equipment, environmental equipment and so on. Installation 1,Inside: There are the installation holes in the base for circuit board or din rail. 2,Outside: The products can be directly fixed on the wall or other flat boards with screws or nails via