AB premium Road OVAL chainrings for FSA are designed for all FSA ABS cranks like Gossamer, SL-K and K-Force light. We only offer "one" chainring model, but due to very special construction it fits all FSA ABS crank models. They are 110/4bcd, but also fit to older 110/5 FSA ABS cranks. This is because new FSA 4 bolt crank is simply a reduced version of their 110/5bcd crank. The 5th bolt behind the crank was removed without any other modification to the crank itself. With Gossamer: Simply use original bolts and spacers, nothing else needed. With SL-K use original bolts & bolt covers, nothing else needed. K-Force light will however require our special bolt covers for that model.