二胡调音器PRO-麦克风自动调音 app for iPhone and iPad
This is an free Erhu Tuner created by ukulele player, a very good tuner you need:
Pro version provides Pic Tabs Collection features,and removes ads.
1. Designed for Erhu.
2. Smart algorithms for the best.
3. Not only D key, but also all Erhu keys.
4. Easy to use.