Pioneer DJ DDJ FLX10 4 Deck and 4 Channel Black DJ Controller and Cover BundlePioneer DJ DDJ FLX10 4 Deck and 4 Channel DJ Controller for Multiple DJ Applications (Black) The DDJ FLX10 is a 4 channel performance DJ controller for rekordbox and Serato DJ Pro. The Pioneer DJ DDJ FLX10 4 Deck and 4 Channel DJ Controller includes a host of brand new features including Track Separation technology, which enables new creative possibilities such as the easy performance of mash ups on the fly with no need to prepare tracks in advance.