This is a silly question but here goes anyways

[adamd]

im trying to figure out how to swim with the tanks like that wonder how he has them attached most i have had is 4 stages 2 for me 2 of buddys who was videoing dive it dosnt even look like there cliped on but its hard to tell

 

[grazie42]

attached to d-rings on a weightbelt...thats how all the cool kids are doing it now...

 

[Trixxie]

Interesting. Where'd you find the picture?

I googled images and searched for "technical diving"