I tried it out yesterday in the swimming pool and it worked well; takes just a tiny puff of air to eq it. I had to be careful with it as it does leak if I just jam it over my head, but it's just the way the goggles fit and not the piping I added. Once they are fitted properly they don't leak. I had tried it in Florida while spearing and didn't like it but those were more hostile conditions and not really suitable for using a new piece of gear. I may try it in home waters this weekend. I am still thinking about how to fashion the nose piece...