For decades I have struggled with a 17.5mm mouthpiece, always feeling like I was about to topple off it. Most of the time I would get away with it but never felt safe. I also play a tenor horn, using a 19mm ID mouthpiece and that is as comfortable as a pair of carpet slippers! So I thought I’d try a larger, 18.07mm mouthpiece for my Yamaha 668v French horn. The security was immediately apparent but initially my sound was quite brash with the 34b and I wondered if I had made a mistake in buying it! Now, after a few practice sessions with the new mouthpiece, my sound is almost back to where it was but now there is more of it when I need it, notes are more secure and articulation seems easier. I am very pleased with the Yamaha 34b and recommend it to anyone who has fuller lips.