... is used on botlles of 207 and 232 bar maximum working pressure (MWP). Check which your bottle is and if your fill pressure is less than MWP then you will get some fills out of the bottle. The number of fills can be calculated using software available on this site (somewhere!).
300 bar bottles use a din fitting (screw instead of 'a' clamp). Clearly for any given fill pressure you get a lot more fills out of a 300 bar bottle.
Thanks for the replys, was going to get a 15ltr 232 bar bottle off fleabay but ive just used the fill calculator and i'll get 86 fills, but i can get 106 fills from a 7ltr 300bar bottle so im going to wait till a 300bar comes along, Kevin