"The worlds most hostile environments are our proving grounds has been the APM Hexseal mission and motto since 1947 when APM first developed its line of switch and circuit breaker high-pressure sealing boots for the U.S Navy. APMs highly IP rated seals are designed to meet MIL-B-5423, are UL recognized, and millions have been used extensively in avionics, instrumentation, communications, construction, marine, medical, and industrial and process industries. APM also offers a full line of UL recognized self-sealing fasteners and washers for panel, electrical NEMA enclosure, and other related systems requiring sealing to 20,000 psig that are also impervious to a wide range of corrosive liquids and gases.