Tub apparatus comprising a foamed, resiliently compressible, plastic tub wall having an inner side and an outer side, the tub having an interior to receive liquid, and ports extending through the side wall; a plastic pack having a cavity formed therein; a pump unit received in the cavity and protectively...http://www.google.es/patents/US5392473?utm_source=gb-gplus-sharePatente US5392473 - Power package for SPA apparatus
