Nile that might be a good shout. Wibble I have bought a AP Inspiration that I collect tomorrow. Everyone at the dive centre I use have them. Also I have got a cracking deal on a unit. jb2cool rebreathers seem to be a better option as our bodys are not 100% efficent so on twins you waste alot of gas. Also on one dive on my course we done a wreck at 40m and by the time i got to the wreck and done a bit of exploring the current was so strong I use loads of gas. All the other guys on rebreathers used hardly any. Twins sets are good if you have a low gas consumtion rate. Also with that rebreather on your back you have a nitrox mixing machine with you so always got the right gas for the depth. The guys I started diving with also do alot of wrecks around 60m and deeper. So the way I looking at it is why spend more money on open circuit training. I might as well just use the money for the rebreather training. John let me know I am up for diving when ever your out diving.