F-Tuba, bell 42 cm, 6 valves , Model 81C (181 6V), 6 (4R/2L), Bell diameter 420 mm (16,535 inch), rotary valves, nickel silver trimmings, spiral spring system, Bore of valve section conical 19,6 - 21,2 mm (0,772 - 0,835 inch), brass body, Material of mouthpipe nickel silver, Mouthpiece TU19, lacquered