St. John Beach Bum store rents the similar Tribord Easybreathe and a few friends have tried them out. They are expensive and really only work well on the surface. If the float ball does not seal well it will dribbly pretty much continuously. But, one friend who was not comfortable snorkeling in the past due to getting water in her very sensitive nose was comfortable with the Easybreathe. I'd be interesting in hearing any first hand reviews of a similar product.

Cheers, RickG