is in the key of G, and the low register extends to the G below middle C; its highest note is a high G (4 ledger lines above the treble staff). The bass flute is an octave lower than the concert flute, and the contrabass flute is an octave lower than the bass flute. Less commonly seen flutes include the treble flute in G, pitched one octave higher than the alto flute; soprano flute, between the treble and concert; and tenor flute or flûte d'amour in B, A or A pitched between the concert and alto. The lowest sizes (larger than the bass flute) have all been developed in the 20th century; these include the contra-alto flute (pitched in G, one octave below the alto), the subcontrabass flute (pitched in G, two octaves below the alto), and the double contrabass flute (pitched in C, one octave below the contrabass). The flute sizes other than the concert flute and piccolo are sometimes called harmony flutes. Construction and materials Concert flutes have three parts: the headjoint, body, and foot joint. The headjoint is sealed by a cork (or plug that may be made out of various plastics, metals, or less commonly woods). It is possible to make fine adjustments to tuning by adjusting the headjoint cork, but usually it is left in the factory-recommended position around from the centre of the embouchure hole for best scale. Gross, temporary adjustments of pitch are made by moving the headjoint in and out of the headjoint tenon. The flautist makes fine or rapid adjustments of pitch and timbre by adjusting the embouchure and/or position of the flute in relation to himself or herself, i.e., side and out. Crown – the cap at the end of the head joint that unscrews to expose the cork and helps keep the head joint cork positioned at the proper depth. Lip plate – the part of the head joint that contacts the player's lower lip, allowing positioning and direction of the air stream. Riser – the metal section that raises the lip plate from the head joint tube. Head joint – the top section of the flute, has the tone hole/lip plate where the player initiates the sound by blowing air across the opening. Body – the middle section of the flute with the majority of the keys. Closed-hole – a fully covered finger key. Open-hole – a finger