FX3 is the perfect solution if you need a special effects controller for Traktor Pro.

The device controls the browser and four effect slots simultaneously.

Special controller for DJ software (optimised for Native Instruments Traktor Pro)
Setup files for Traktor Pro/Duo in current version 1.2.4 or higher are shipped with the controller
USB interface - class compliant / no driver necessary
4 FX slots available – access to all 4 FX slots simultaneously by 16 pots and 20 buttons
4 presets per FX slot to store FX types and FX modes (advanced/chained)
About 120 commands – all freely reassignable
Browser section with a dedicated encoder and 4 load buttons
25 coloured buttons
All controls with double function by holding down the shift button
17 LED’s in different colors to display various informations
Indication of all FX button states by feedback data from computer software
USB bus powering –  consumption less than 500mW / 100mA
Very compact design in a black, plastic casing (desktop format 180x105x70 mm, 350 g)
High-quality faders, pots and encoders from ALPS
New rubber knobs for best tactile feeling
 
System requirements

PC or Mac with a free USB port (1.0 or higher) or any USB hub
Native Instruments Traktor Pro/Duo (as of version 1.2.4) or software which allows user assignments of continuous parameters (CC) and note commands.