I have now used the snorkel a week in the Red Sea and have to say that it is worth it to get a high quality snorkel as this. No comparison to the usual nonsense which one buys on the road on vacation. The valves function properly. Even with bigger waves come in here no water. Also very handy when diving down in between times while snorkeling. Valve makes them immediately and should something a little water to come in that is indeed collected at the bottom and can easily be blown out through the bottom valve. I was also impressed by the mouthpiece. It has a perfect fit and does not interfere, even after 2 hours in the water. Other buyers reported by the bitter taste of the mouthpiece. I can not confirm this. Completely neutral in taste and smell.