The CostGardā¢ 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 in more than twenty years of successful field operation. Tens of thousands are in operation in various facilities, indoors and outdoors, in every state in the United States plus Puerto Rico, the District of Columbia, and several foreign countries. Not one has become blocked or failed to operate correctly.