I bought one of the last sets from Performance about 8 years ago. They had a rubbery plastic plug that fit into the beams and you would insert the wings and keep them in with a pin. Apparently, the company that made the plugs doubled the price, which made them too expensive to produce. The kit was like $1500 at the time. I had them on my P18-2 and thought they were great. I've been thinking about building a set of the sport wings (like Hobie Europe makes) for my Supercat.