Small but very precise tuner that tunes your instrument fine and very fast. First of all I can mention is its size - it is very compact and can fit even in full packed pedalboard. Same as TC Electronic Polytune mini, probably size is the same. Another great option is that it has very well readable bright LED display so there are no problems to use it on open air stage in strong light or sun.
Tuning itself is also very precise. Compared it with Boss TU-3 and can say, that they are almost equal. Mooer reacts quite fast on pitch changes and it comes handy in case of tuning in between songs during live gig. Tried this tuner not only six and seven string guitars but also on five string bass and can say that there are completely no problems with fifth string even if you have it tuned lower than B (at least A it ?understands? correctly enough).
Unfortunately I couldn?t find any information if it is support additional tuning presets besides 440Hz, but I think it is not major disadvantage of it because such case appears rarely. One more thing that I want to pay attention is that according to manual it has true bypass, however a lot of tuner pedals has buffered one because a lot of players place it as first pedal in chain. It is not major problem but if you count on buffer to compensate your signal this may not be tuner of your choice.