This is a new version of the classic King 3B trombone, introduced in October 2015. The difference between this 3BL and the standard 3B is that this "L" version has a lightweight nickel hand slide. The outer tubes are thinner, and are drawn without the thicker extrusions near the hand brace. This is similar to how the King 2BL Jiggs Whigham trombone hand slide is designed.
Specs