 When the performer is putting on a new string, the fine tuner for that string is normally reset to a middle position, and then the peg is turned to bring the string up to pitch.The fine turners are used for subtle, minor adjustments to pitch, such as tuning a cello to the oboe's 440 Hz A note or to tune the cello to a piano.The endpin or spike is made of wood, metal or rigid carbon fibre and supports the cello in playing position.