The XR Drivers get their names from being experimental. The Xr03 does not have inverted cone technology. In Europe they are only available in non-conforming versions. The XR05 and XR05 Cti come with a Rayon shaft but this is nothing like the tour version of the Rayon it is a lot softer as this club is aimed at your hackers and will probably go to high and the shaft will be to soft for better players. There are 15 grams removed from the crown and also 15 grams taken from the walls of the Xr05Cti this weight is placed low and back to help joe punter hit it up in the air. I don't know how this club performs with other shafts as we have not been offered custom flavours in the UK. Hope this helps.