I just bought a ring and bag from stealth marine (maker of the Stealth F16). It's a nice aluminum ring with a mylar bag. I haven't installed it yet (I'm still waiting for the spi to come back from the sailmaker...). I've done a review of the setup on the cats sitting the parking lot at my sailing club and this looked like the best bang for the buck: it's a good design, and I got the ring and the bag for the price some charges (*cough*nacra*cough*) for just the ring...