Endless Swim Pool Question

I couldn't find an appropriate place for this question so hopefully it is okay here. I saw a billboard for an endless pool but instead of an apposing water flow the swimmer had on a harness with a rope or bungee cord attached to the deck. You just swim and stay in one place. So simple! Is that setup something commercially available? I dont even know what to call it for a Google search.

I've seen stuff like that on pool supply sites like inyo pools. I'd search "pool exercise equipment.

Thanks, that got me in the right direction. The key search text turned out to be "stationary swimming". That's a no brainer. :-) Here is what I found that seems perfect for what I need. http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER