Since I like snorkelling, I've been following the 'full face snorkel' controversy for some time. There is a ton of physics in this. Basically, the first version was just a full face mask with a snorkel tube. That ended up killing people, or knocking them out because the large volume did not allow for the co2 to clear. Thus you were breathing back your breath.
Now we have a new version which looks like Antman. It has two tubes, will ball valves. There is an inner mask for breathing. So you suck in with the tubes, and breath out with the front valve. Neat. There is an amazing little valve for draining water.
You can jog with this one, although someone will call the police. We've tested it at the cottage, and all say they will never go back to an original snorkel. It is good for shallow dives, but the large volume adds buoyancy. You come up and breath again, you don't need to blow tubes. My son could do a full front-crawl sprint with it. His girlfriend could swim hard, but not a sprint.
We used it to clear weeds. I'm taking it on my next trip. For my wife I ordered a pink one.
I just added the cheap action camera, which fits on the snorkel.