It's a tube usually for snorkeling and it work well for waterproof when you meet waves or under the water.You can use it to breath when you snorkel and you can get a free-diving under water 98′’,the
snorkel can keep dry because of the technology of the snorkel.
How it works?
The most
normal dry snorkel is working with a special floating design ball or bubble and it will float to fill the top vent when it meets water and keep water off.
What is your suggestions to choose it?
Usually it will have two system to make sure it work well,one for breath and one for draining,we need to have a test when we start to use them to keep safe and good experience.It will be better if you can get a test in your bathtub use a balloon or you can get a test by yourself to have a check.It will have a delay about the floating system so it's a balance for waterproof.The balance is what we need to check.Some snorkel is not good enough to keep balance and some will have trouble about the floating system or draining system and can't function as we wish.
Of course you also need to check the mouthpiece and clip.
Hope you will have a good experience for snorkeling!