Key: Bb Bore size: ML (0.460" ; 11.70 mm) Main tuning slide style: H (Standard, two roots) Bell material: Silver Bell size: S (# 37) Bell thickness: S (0.024" ; 0.60 mm) Bell diameter: 4.843" (123.00 mm) Finish: S (Silver) Leadpipe material: Silver Tuning slide material: Inner / Outer Silver 1st tuning slide finger hook 3rd tuning slide adjustable finger ring & stop screw