I looked into these a few years ago and found out that the ABS versions infringed on a US patent. I believe the 3g version have a leather trim around the outside of the removable slide sole and also have that hole in the center of the removable heel. This allows them to get around the infringement in the US. I did hear that someone was able to get a pair of the NV-4 style from a Canadian pro shop. The NV-3 are pretty identical to the Tour Ultras from 3G, other than the bottom areas that I pointed out.