The B&S 3198 is a 5/4 size BBb Tuba features 4 rotary valves with the 3B linkage system. 3B ball bearing linkages on both ends of the valve connecting arm provide the ultimate in smooth and quiet operation. It has a .748" bore (4th valve: .787"), a bell diameter of 18.898" and a height of 38.976". It is constructed of gold brass and boasts a clear lacquered finish. Gig bag included