if you are referring to the length of the threaded portion of the fill adapter which screws into the din thread of your diving cylinder then you fill adapter is a 232bar adapter and your diving cylinder is 300bar. 300bar cylinders have a deeper thread to stop you connecting them to a 232 bar system. You can buy a spacer which fits between the filling adapter and the bottom of the cylinder thread. I made one and best fittings also make one. The other way is to buy a 300bar filling adapter or one which fits on the end of the whip.
http://www.bestfittings.co.uk/shopexd.asp?id=637
http://www.bestfittings.co.uk/shopdi...=129&cat=Steyr