Last week at the flea market, I spotted a Hoover Concept One model U3307. Being a power drive model, the base has its share of paint scuffs and scratches and the bag has slight tears at the corners, the seller wanted $20.00, I offered 15., which he turned down. Today I saw the same cleaner there again, and this time he accepted my offer. I'm not a huge fan of Concepts (I'd take a Dial-A-Matic over a Concept any day of the week), but I liked this one's mint green color. With only a fresh Type A bag, it cleaned my red carpet beautifully. I'm thinking maybe I can use Mr. Clean Magic Erase on the base. Any idea when it was made and what the top of the line model was at the time? It's serial number 00018747.