Medical devices for therapeutic rehabilitation, maternity, and hydrotherapy, namely, pools, sitzbaths, bath tubs, hot tubs, whirlpools, spas, and relaxation pools; medical devices for therapeutic managed care of the elderly, namely, pools, sitzbaths, bath tubs, whirlpools, spas, and relaxation pools; medical devices for therapeutic treatment, rehabilitation and maternity care, namely, air bubble devices for hot tubs, pools and water jet systems