Recording Time per 128MB depends on the sampling rate, a higher recording sampling frequency brings better recording quality, but takes more memory space. Below is the recording time with different sampling rate: 8000 Hz — 8 hours ; 11025 Hz— 5.8 hours ; 16000 Hz—4 hours ; 22050 Hz—-2.9 hours ; 32000 Hz—-2 hours. If the memory capacity is bigger, the recording time will be longer, for example, 256MB has maximum 16 hours recording time.