Most gadgets overblow at two times the rate of the primary frequency the octave, but as the clarinet acts as a closed pipe system, the reed cannot vibrate at twice its original speed because it can be creating a 'puff' of air at the time the previous 'puff' is returning as a rarefaction. This means it cannot be bolstered and so would die away. The chalumeau sign in plays basics, whereas the clarion register, aided by the register key, plays third harmonics an ideal 12th higher than the basics. The first a few notes of the altissimo range, aided by the sign up key and venting with the first left hand hole, play fifth harmonics a big seventeenth, an ideal twelfth plus an enormous sixth, above the fundamentals. The clarinet is hence said to overblow at the twelfth and, when moving to the altissimo sign in, seventeenth. By comparison, nearly all other woodwind gadgets overblow at the octave or like the ocarina and tonette do not overblow at all. This overblowing behavior explains the clarinet's great range and sophisticated fingering system. The fifth and seventh harmonics are also accessible, sounding a further sixth and fourth a flat, diminished fifth higher respectively; these are the notes of the altissimo sign in. This is also why the internal "waist" dimension is so important to these harmonic frequencies. Clarinet bodies have been made from loads of elements adding wood, plastic, hard rubber, metal, resin, and ivory. The overwhelming majority of clarinets utilized by specialists are made from African hardwood, mpingo African Blackwood or grenadilla, rarely as a result of diminishing provides Honduran rosewood and often even cocobolo.