I used this on Saturday during my open-water swim. It works exactly as advertised, and I couldn''t recommend it more. The belt that fastens around your waist as well as the cord attached to the buoy are both fully adjustable, so you have some control over the position of the buoy as it floats above you, so it doesn''t interfere with your swimming. I didn''t feel it once, and wouldn''t have even known it was there, which is exactly the way it is supposed to be.
As well, I stood on the shore and observed other swimmers in the water at distances of between 100-300 meters, some with this device and some without, and the swimmers with the buoy were MUCH more visible then those without. That in itself is worth the purchase.
Lastly, it''s a flotation device. So if you get in trouble, you can use it as such.
In summary, get this device and you will have a much better chance of being seen, and you''ll have something to potentially save your life, should you need it.