Pioneer Dj DDJ-FLX10 4-Channel DJ Controller for rekordbox and Serato DJ Pro (Black) - Manual (Page 38)

Part names and functions
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17 Enlarged waveform (playing deck)
Displays the enlarged waveform of the playing deck.
18 Enlarged waveform (deck for mixing)
Displays the enlarged waveform of the track on the deck for mixing.
19 MASTER
Lights up when the deck is set as the master.
20 Cue point
Shows the position of the set or called-up cue point.