The c & g tuners are 2 tuning forks. They are based on the pythagorean or just scale, also known as whole body tuners. These are c 256 and g 384 hz forks. Note:- All tuning forks are tested with +/- 0.25% accuracy and all pipes, chime bars are tested with +/- 0.5% accuracy. At times there may be import duty payable for buyers other than USA for which we are not responsible and is to be paid by you.