These Yamaha Standard brass mouthpieces are produced with advanced computer design and manufacturing technology for unmatched precision, smooth attack and easy playability. They have an ideal weight for all-around use and available in a variety of configurations to suit every player.Compare to:TR11: Schilke 11TR11A4: Bach 7ETR11B4: Bach 7DTR11C4: Bach 7C, Giardinelli 7CTR13A4a: Schilke 13A4aTR13B4: Bach 6CTR13C4: Bach 6BTR13D4: Bach 6TR14A4a: Schilke 14A4a, Giardinelli 6STR14B4: Bach 3C, Schilke 15BTR14C4: Giardinelli 5CTR14D4: Bach 5BTR14E4: Bach 3C rim, very deep cupTR15B4: Bach 2C, shallower cupTR15C4: Bach 2CTR15E4: Bach 2C rim, very deep cupTR16C4: Bach 1-1/2CTR16D: Bach 1-1/2C, deeper cupTR16E4: Bach 1-1/2C rim, very deep cupTR17B4: Bach 1-1/4CTR17C4: Bach 1CTR17D4: Bach 1C, deeper cupTR18C4: Bach 1TR5A4: Bob Reeves OES 69TR6A4a: Schilke 6A4aTR7A4: Purviance 4 (4*D4)TR7B4: Schilke 7B4TR8C4: Bach 10-1/2C, Giardinelli 10CTR9C4: Bach 7C with smaller rim diameter