This is an important device for helping your swim stroke. It tells you when you have rotated your hips far enough, which for most people from a non swimming background is usually not far enough. I ran just as fast as the winners yet my swim was too slow and this device played a big part in making my stroke correct.
Check it out at http://www.swimoutlet.com/product_p/2323.htm
I also have pictures of mine if you want. I am asking $20