Tried the cylinders in 2 ways. 1 was at 500 psi. they were beautiful! Lots of freedom. So I later filled them & then dove them,..... Well.... Not so good. They were enormously heavy so I had to keep my wing quite full & the weight of them pulled down so hard against my hips that I could barely move to frog kick. What a disappointment. Well back to the Al 80’s I’ve been using & now I have to figure out what to do with a pair of Faber MP71’s....