Shown below is the Quake Virtual DJ P.F.L. Utility.
About The Quake PFL System - With The Addition of a second sound output device, the unique PFL system allows independent monitoring of both Track Play Decks and the Sound Bite Deck. In essence, the PFL system functions identically to one of the Track Play Deck, except that all sound output is routed to a secondary sound output device intended to be connected to a pair of Ear Phones.
Totally Independent - The PFL System is used as an aid to cueing or previewing a track prior to playing. Using the simple controls, you can, without effecting the track in the Play Deckin any way, advance or rewind a track to any position, then by clicking the Synchronize button, set the Play Deck track position accordingly.