"The world’s 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. APM’s 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.