Check this thing out. I was fascinated on how it forces the person to take the correct grab and catch, and, look at the little kicking levers there: check it out at the link above. There’s other pictures on it.
And…it’s 2500 bucks.
we have on at our training facility and our experience with it has been marginal. despite the claim, it really does not force you to do anything correctly and getting the resistance right so that you can do the simultaneous kicking and pulling is a chore. on paper it’s sweet. wanna buy a used one?
Until they devise one where you get the proper shoulder/hip roll, ehhhhhhhhhhh. That looks like a shoulder wrecker.
I think you’d be better off just swimming. 
-Robert
Not only a shoulder killer but a back killer as well. My lower back muscles got all tensed up just watching the twisting going on in the video clip.
shoulder and neck wrecker…ouch…
Cool idea- They need to improve it so that you are somehow hanging so you can get the body roll. 42500 buck buys a lot of annual swim passes!