The swift was Gaastra's less expensive and lighter cambered sail some of the earlier models were super light and great for women and smaller sailors that wanted control and performance at a reasonable price In 2005 things changed and the swift became a very high performance sail, heavier and basically the same as the gtx. So we have a mixture of them. The 4.5 and 10.0 are the wonderful and inexpensive earlier models. The 6.8 and 9.0 is the newer higher performance one.