The outer slide is nickel-silver for durability and the valves are in an offset configuration. This model is lighter than the others, making it easier to hold and giving it a very quick response. Designed with the budget-conscious band director in mind, this new professional bass trombone has a smaller bell size that offers excellent tone for the advancing bass trombonist. Specifications Level: Professional Bass Key of: Bb / F / Eb & Bb / F / D Bore: LL: 0.563 Bell Diameter: 9 1/2 Shank: Large Leadpipe: Gold Brass; Fixed Body Material: Yellow Brass Bell Material: Gold Brass; One-Piece; Hand Hammered Weight: Standard Finish: Clear Epoxy Lacquer Inner Slide: Chrome-plated nickel silver; Drawn Outer Slide: Nickel silver; Drawn; One-piece Mouthpiece: 58 Feature:s D Slide Included Pistons/Rotors: Two; Offset; Dependent; Hand lapped; Mechanical linkage