The SV2 combines the same Scupper Valve lower section with the sleek and effective SV2 Semi-Dry top. The SV2 Semi-Dry top horizontal vents (1) are engineered to diffuse splashed water that would normally freely enter the snorkel top. The small gaps between the vanes (2) of the vent restrict water speed and droplet size and permit most of the splashed water to exit the special vents (3) without entering the breathing tube. Thus, you get less water in your snorkel. The SV2 is the perfect answer for rough or choppy water conditions.