Double Horn & Triple Horn & Double Wagner Tuba All Double Horn models are manufactured with 11.8 mm bore and bronze bearing cover Custom models with different bore sizes are available on request Over 100 different Double and Triple Horn models in 25mm or 27mm are available on request Change valves for K-model in 20mm / 22mm / 24mm / 27mm as well as a sound valve for F pitch are available on request For bore size 11.8 mm slides and bows can be delivered on request Wagner and Double Wagner Tubas are available in bore sizes 11.8 mm, 12.5 mm and 13.5 mm