The jet pack in the video runs off of water. It's the first of its kind. The tube you see attached to it, that goes into the water, goes into a gas powered small boat that follows whenever the jet pack pilot is flying (if you look close in the video you can see it).
The jet pack itself is super safe. It's actually approved for the water by the coast guard, and there is nothing illegal about it :) You need to be at least 18 years old to fly it. It takes about 30 minutes to an hour of training, and then you're set. These water jet packs are going on sale very soon, and you can contact the company to get on their waiting list. You can contact them here http://www.jetlev.com And you can find out a lot more about them on the website.
The jet pack is able to fly purely by the volume of water that comes out of the two hoses that are attached to it. It shoots out 10 times more water volume then a fire hydrant does. You can stick your hand right where the water comes out, and you won't get hurt at all, as you can see several times in the video.
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