I go under waterfalls, through rapids, and in the surf. Round snorkels get wobbly in the current... this one doesn't. It is an oval shape which means it has a high capacity but a lower overall cross section. For me that is a good thing. It also has a purge valve on the bottom, and a unique design on the top... so even in rough water and waterfalls I can do what I really need to do... BREATHE! I lost my original one... and buying this as a replacement... no other one will do.