Hi , Its realy helpful to get a box with a third row of bottons.. For a c&g the top row would have a B d and other flats and sharps.. For sea shantiys its worth saving a little more.dow. If you are in the USA look at Elderley instroments or the end of all box heavens look at the Botton Box in Amherst MAss.. Sorry asking you to spend an exstra $ 250.00.. I think a 30 botton BAstary is more like $350.00 or more.. Myself I would not spend almost $200.00 on this kind of instroment.. If you do think more on this one please make shore the bellows are holding air.. When you go to play a note if you feel the bellows are'nt "holding the note or feel "Airy" the instroment may need a new bellows and on a bastri 20 botton that is not worth persuing even if the instroment was free.. (Only an opinion of cource) Good luck.. Yours, Guy