Honeywell's HE Series features true hermetic sealing with metal-to-metal and glass-to-metal design and manufacturing processes. The hermetically sealed HE Series limit switches are an effective solution for harsh applications where the atmospheric pressures and temperatures exhibit significant variations such as in commercial and military aircraft. With a 300 series stainless steel bushing and housing, the HE limit switch is able to resist most severe environments with the environmental and hermetic sealing. Select HE Series catalog listings are qualified to MIL-PRF-8805 standards. HE Series limit switches are designed with either a 5/8 inch or 15/32 inch diameter threaded bushing for panel mounted applications.