The 101GS is similar to the Bach 5GL, which is a somewhat obscure mouthpiece resembling a Bach 5G, but with a slightly shallower cup, splitting the difference between the 5G and 5GS. It is a bit deeper than the Bach 5GS. Although the Bach 5GS and Schilke 51B are sometimes equated, the 51B is actually more similar to a Bach 6.5AL. The 101GS is also similar to the Remington mouthpiece.
The 101GS has an ID of 1.01 inches, a .270 (.686mm) throat, and is available with a small or large shank.