Graph Tech PRB-4221-C0 Ratio 2+2 Electric Bass Guitar Tuners (Chrome)Graph Tech's calibrated and synchronized tuning system makes tuning and retuning your bass faster and more intuitive. On the fly adjustment has never been easier!. Each string position has its own calibrated gear ratio, so each string feels and responds the same to any tuning adjustment. A full rotation of any key results in a change in pitch of a full tone (more or less). From Low E to G, the gear ratios are 48: 1, 36: 1, 25: 1 and 23: 1. In order to