As I've posted before, I've got a nickel allergy. So, everything has got to be stainless steel. I tried other hypoallergenic metals, but reacted to every last one of them. I have a Houser SF that plays well, but was not as responsive as I wanted, and a little bright. I asked Mr. Houser to make a C15 using a C10 depth. It is a rocket! As perfect notching as I've ever seen, centered tone, very warm sounding, and even from the basso range up to A above the clef. Still working out the Bb, B, C, simply because it is a little deeper than what I've been playing by about 3/32" it needs a little more air. Mozart is very delicate with it, I can still put a ton of air through it, but it activates with so little air that the pp are just great to play, even on a big Paxman 25A. Only played 2 hours total on it, so more to come. I've encouraged Mr. Houser to make another one of these to take around to shows and get a pro's opinion, but I think with extremely minor tweaking, maybe an even slightly smaller bore (like a 17) it could be a great mouthpiece. As usual, the finish is top notch, with beautiful, clear lettering, flawless threads, and a near razor blade end to the shank, giving a very even, smooth blow. Recommended.