GR Mouthpieces are being played by the world's top call brass musicians, plus GR is the mouthpiece of choice for the finest performers, educators, and students.

• The GR 63 Series can be described as being between a Bach 7 cup diameter and a Bach 10 1/2. With various rim contours, alpha angles, cup volumes, and backbores, the GR 63 Series has many options for players who use this popular size.

• The GR 64 Series can be compared to a Bach 7 cup diameter.
  With various rim contours, alpha angles, cup volumes, and backbores, the GR 64 Series has many options for players who use this popular size.
  
  
• The GR 65 Series cup diameter is similar to a conventional 5 diameter. Classic Blank is standard. Symphonic Blank is standard on the C** and C models.