Pioneer Dj DDJ-FLX10 4-Channel DJ Controller for rekordbox and Serato DJ Pro (Black) - Manual (Page 26)

Part names and functions
26
En
11 KEY SYNC button
Press:
Changes the key of the track to match the other deck.
[SHIFT] + press:
Changes the key of the track on the deck that is playing to the original key.
12 TEMPO RESET button
Press:
Returns the playback speed to the original speed, regardless of the position of
the
[TEMPO] slider.
[SHIFT] + press:
Switches the range of the [TEMPO] slider each time the button is pressed
while holding the [SHIFT] button.
Switch between [±6%]  [±10%]  [±16%]  [±100%]  [±6%] .
13 HOT CUE mode button
Press:
Enters Hot Cue mode.

Read more: Using Hot Cues (page 126)
Hold:
Enters Saved Flip mode.

Read more: Using Saved Flip (page 134)
[SHIFT] + press:
Enters Pitch Play mode.

Read more: Using Pitch Play (page 129)
14 PAD FX1 mode button
Press:
Enters Pad FX mode.

Read more: Using Pad FX (page 127)