Key: Bb Bore size: ML (0.460" ; 11.70 mm) Main tuning slide style: H (Standard, two roots) Bell material: Y (Yellow brass) Bell size: S (# 37) Bell thickness: S (0.024" ; 0.60 mm) Bell diameter: 4.843" (123.00 mm) Finish: L (Lacquer) Leadpipe material: Yellow brass Tuning slide material: Inner / Outer Yellow brass 3rd tuning slide adjustable finger ring & stop screw