The KB & KDB drain and breather are installed either the bottom top of an enclosure. When installed in the bottom they act as a gravity fed drain to expel moisture from condensation that can build up in electrical enclosures When installed in the top of an enclosure it acts a s a breather allowing air to enter and prevent a vacuum which can cause the drain not to flow properly. They are UL / cCSAus / FM certified for Class I Class I Zone 1 & 2 Class III, Type 4 & 4X. Also, ATEX, IEC Ex, Ex db IP66 with suffix CEN. Review each part for hazardous rating suitability and notified body. The KB & KDB are offered in aluminum, 300 series stainless steel and 316 stainless steel. Thread sizes to 1/2 NPT and Metric sizes M16 & M20.