I bought this Ar resonance backbone 40 M bronze mouthpiece bottom to add to a 40 XS brass mouthpiece bottom and M lead and MC tops I already own, to give me more versatility in my setup. The XS backbore despite the name is similar to a standard backbore found in for example most Bach and Yamaha mouthpieces . The M lead with the XS backbore is my go to lead mouthpiece, with the MC cup I get a bigger sound, but I wanted to push it further and the M bronze backbore with the MC cup is perfect for playing in most situations. The bronze gives a very vibrant and resonant tone, response is faster, you can feel all the slots more securely I highly recommend these mouthpieces in whatever combination you might choose.
