Two vertical stabilizers—often smaller on their own than a single conventional tail would be—are mounted at the outside of the aircraft's horizontal stabilizer. This arrangement is also known as an H-tail,[1] as it resembles a capital "H" when viewed from the rear. The twin tail was used on a wide variety of World War II multi-engine designs that saw mass production, especially on the American B-24 Liberator and B-25 Mitchell bombers, the British Avro Lancaster and Handley Page Halifax heavy bombers, and the Soviet Union's Petlyakov Pe-2 attack bomber.