Grundig CDS2600iP Instruction Manual page 20

During playback, repeatedly press the SKIP/TUNING or buttons to
skip to higher or lower numbered tracks. Playback will begin on the selected
track.
During playback, depress and hold the SKIP/TUNING or buttons to
search within a track at high speed to locate a specific musical passage.
Release the SKIP/TUNING or buttons when you hear the desired
passage.
Normal speed playback will resume at that point.
18