The ExerSwim (TM) swimming pool flow generator provides a strong and steady current in swimming pools, allowing endless swimming in even the smallest pools. It saves you from having to spend tens of thousands of dollars on a flow pool, and works in any pool. (We've even used it successfully for an above ground pool.) Believe me, this is a steal - They cost several thousand dollars new and are extremely reliable. See http://www.exerswim.net/pages/products.html for pictures and details. The one we're selling is a used one, but works fine and has two brand new marine batteries. This ad has had 8,817 displays and 218 readers