Depending on the particular design of the airway, this feature could actually increase breathing resistance at high flow rates or make it more difficult to clear a completely flooded snorkel. It may also add to drag through the water, causing the snorkel to wobble. Some dry airways are an add-on, so you can use the snorkel with or without them, switch them between snorkels or put them on later. These small baffles of plastic or silicone near the reservoir and bottom purge valve appear to improve both the clearing and dryness of these snorkels. Although only eight of the 26 snorkels tested had these, all eight scored well.
Adjustments Being able to adjust the position of the snorkel mouthpiece adds to fit and comfort.
Most adjustable snorkels simply allow the silicone section of the mouthpiece to swivel on the snorkel tube. Some use a pivoting or rotating section in the hard plastic tube, although we found these prone to leaking. Mouthpieces Many of the better snorkels now have a scuba-type removable mouthpiece. This makes it possible to change the mouthpiece to fit your needs or to replace the mouthpiece when it becomes worn. Some mouthpieces are offset at an angle, but we could not find any performance difference based on this feature.