Beware of Harold Duran, HD Stores, of Miami and Palm Coast Florida. He called saying he was a patient wanting to buy a portable concentrator and emailed a prescription. I called the MD who was in New Jersey and he had never heard of or seen the patient before and the prescription was fraudulent, full of misspellings and not from their office. Do not deal with him. He gave an Am Ex for billing but no idea if it is valid. Mailing address on NW 66th Street in Miami was a warehouse and no one by his name had a business there.