Hi, I am sorry that I didn't see your comment/question until now. The tank inside the black tool belt is C02... That size is popular with the paint ball crowd. The larger tank that it is strapped to is a 5 gallon beer keg (soda keg in a previous life)
I applaud your creativity and ingenuity. I have never seen a CO2 tank with this design. What is the little tank for? All the tanks at my work just look like cylinders of propane gas. It seems like the second tank would present a hazard. It was probably a wise idea to secure it.
