Jensen DMR2116i Owner's Manual page 34

Selecting a Track Up/Down
When playing a track, press the button or button to play the previous or
next track in the current category. You can not enter the next category.
When playing a track for more than 1 second, press the button to play the
current track from the start of that track.
When playing a track for less than 1 second, press the button to play the
previous track.
When playing a track, press and hold the button or button for several
seconds to play in fast reverse or fast forward. Release the button to resume
normal playback.
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