The sound of the beep: negative, otherwise very instinctive and practical

In use, the piano, beyond 108, the sound is sometimes annoying.
A good point, we can lower it.
For children, it is a priori ok as simple and instinctive operation.
It automatically turns off if you forget it on.
Very handy little folding up system for vertical support.
Solidity check over time.
Dimensions mini, can take easily.
Battery operated: one LR03 supplied.
Attractive price to less than 13.