For tuning guitars!
Tuners are mainstream and we recommend tuning them in the tuning fork to train your ears.
Tuning with ears and tuning forks not only can you tune quickly, but also have many advantages such as slicing strings at actual timing and developing pitch in the ensemble.
The TF-A is tuned with the common "A=440Hz", and if you are skilled you can create "442Hz" 2 times by adding a degree of looseness once a second.
Make sure you get the most out of tuning with this TF-A.