The tip with the KORG tuner I got from my nephew, who - like me - is a professional musician. He needed it to tune the harp, - I need it only for a proper A with 443 Hz. It can be calibrated, - that is, from the default setting 440 Hz to 443 Hz, for example, ask. When you enter the A of the violin, the pointer is very stable in its display and does not wobble around like in some other tuners. Even a sound output is possible - for someone who requires this feature. Easy to use, functional, reasonably priced. Strong buy recommendation from me.