The Cressi Alpha Ultra Dry Snorkel features a float valve and splash deflector at the top of the snorkel and a purge chamber and one way valve at the bottom to create a snorkel that is ideal for first time snorkelers and those that aren't confident in the water.
The top valve has two functions; first to direct splashed water away from the tube opening and second to close the opening if the top of the snorkel descends below the surface.
The Alpha Ultra Dry has a semi rigid top section that allows the snorkel to be crushed and deformed and it'll still return to its original shape, increasing the life of the snorkel. The lower section is corrugated silicone that allows the mouthpiece to be perfectly positioned for comfortable use. An adjustable quick release strap retainer clip allows the snorkel to be adjusted vertically and easily separated from your mask for washing and storage.
The bottom section houses the purge chamber and one way valve. Any water that does enter the snorkel collects in the purge chamber and either drains out naturally with gravity or can be forced out with a snap exhale.