Save your money. Instead, get a tuner/metronome like the Korg TM-40, which sells for under $30, and use it as described in a wonderful article by
Howard Niblock, the oboe teacher at Lawrence Conservatory. http://www.lawrence.edu/dept/conservatory/studio/oboe/practice.shtml
A metronome is essential for the ultra-slow practice you must do to get your scales and arpeggios into your muscle memory.