the United States Marine Band adopted it. Versions with the characteristic extra 90° bend making a forward-facing bell were developed in the early 1900s. Early sousaphones had bells, with bells popular in the 1920s. From the mid-1930s onward, sousaphone bells have been standardized at a diameter of . Some larger sousaphones (Monster, Grand, Jumbo, Giant or Grand Jumbo, depending on brand) were produced in limited quantities. Construction The sousaphone is a valved brass instrument with the same tube length and musical range as other tubas. The sousaphone's shape is such that the bell is above the tubist's head and projecting forward. The valves are situated directly in front of the musician slightly above the waist and all of the weight rests on the left shoulder. The bell is normally detachable from the instrument body to facilitate transportation and storage. Except for the instrument's general shape and appearance, the sousaphone is technically similar to a tuba. For simplicity and light weight, modern sousaphones almost always use three non-compensating piston valves in their construction, in direct contrast to their concert counterparts' large variation in number, type, and orientation. Both the tuba and sousaphone are semi-conical brass instruments. No valved brass instrument can be entirely conical, since the middle section containing the valves must be cylindrical. While the degree of bore conicity does affect the timbre of the instrument, much as in a cornet and trumpet, or a euphonium and a trombone, the bore profile of a sousaphone is similar to that of most tubas. To facilitate making the mouthpiece accessible to players of different height or body shapes, most sousaphones contain a detachable tubing gooseneck which arises from the lead pipe on the upwind side of the valves. One or two slightly-angled bit(s) (short tubing lengths) are inserted into the gooseneck, and then the mouthpiece is inserted into the terminal bit. This arrangement may be adjusted in height and yaw angle to place the mouthpiece comfortably at the player's lips. Materials Most sousaphones are manufactured from sheet brass, usually yellow or silver, with silver, lacquer, and gold plating options, much like many brass instruments. However, the sousaphone (uniquely) is also commonly seen manufactured from fiberglass, due to its lower cost, greater durability, and significantly lighter weight. The weight of a sousaphone can be between and . Pitch Most modern sousaphones are made in the key of BB (Low B Flat) and like