The CostGard™ HVAC Condensate Drain Seal is inherently reliable. It is simple, has no moving parts, is self-cleaning, self-regulating, and maintenance-free. This reliability has been proven during more than three decades of successful field operation. Tens of thousands are in operation in various facilities, indoors and outdoors, in every state in the United States, including Puerto Rico, the District of Columbia, and several foreign countries. Not one has become blocked or failed to operate properly.