Bob Reeves 41GG 19 5 This is a Bob Reeves 41GG 19 5. Rim: 41 Cup: deep-S Backbore: 19 Shank: #5 This was custom-made by Bob Reeves for me, with the Gary Grant type mouthpiece except for the rim. The "19" lead backbore is a completely new design from Bob Reeves, a company with a 55-year history. It was developed to pursue the efficiency, consistency, and accuracy that modern lead players demand, achieving outstanding responsiveness and stable high-order harmonics. It was named "19" because it was developed in 2019. Compared to the existing "692s" backbore, the resistance is slightly lighter, but you can feel high efficiency. For the past three years, the "19" lead backbore has been available for pre-order as a custom order, but the product version reflects the specifications with the overall balance readjusted based on feedback from professional players in Europe, America, and Japan. (Reference: Joy Brass) Used a few times. I purchased it directly from Bob Reeves in the US, and the new price was over 50,000 yen at the time. Please consider.