You can set your device to automatically record whenever sound above your designated level is detected.
84% have it
3. has an external memory slot
The device has a standard memory slot (such as an SD or micro SD card slot) so that you can either extend the internal storage with affordable memory modules or you can retrieve data, such as photographs, easily from a memory card.
49% have it
4. Has an A-B repeat feature
You can use the A-B repeat feature to mark the beginning and ending of a particular passage of a recording that you want to listen again and again.
30% have it
5. Has a noise cut function
The noise cut function make play-back clearer, with low background noise.