A shoe includes an assembly inner-sole and outsole with openings formed therethrough and one or more unidirectional air transfer sets disposed between the openings in the outsole and the openings in the inner-sole. The unidirectional air transfer set includes tissues separated by a breathable, waterproof...http://www.google.es/patents/US5588226?utm_source=gb-gplus-sharePatente US5588226 - Unidirectional air transfer system for shoes
