Atomic aquatics sv2 semi dry snorkel the atomic aquatics sv2 semi dry snorkel is small and versatile, sleek and valuable, and features a scupper valve for easy use. That's why it's called an sv. Thebines the scupper valve lower section with the sleek looking semi dry top. The horizontal vents diffuse splashed water that would normally freely enter the top, and the small gaps between the vanes of the vent restrict water speed and droplet size, while also permitting the splashed water to exit the special vents. Your snorkel includes a quick disconnect keeper, sliding snorkel keeper, and rotating mouthpiece.