The KB7901 System X Doubling Peg by Hamilton Stands is for holding a brass musical instrument. It can be used for mounting Bb/C/D/Eb trumpet, coronet, flugelhorn and straight soprano saxophone. It is supplied with a removable adapter to mount the peg to your System X stand. The flair of the bell cup, the size of the bell bore adapter, and the length of the bell bore tube are all adjustable. The System X stand is sold separately.