The Native Instruments Traktor Z1 is the ultimate, stick-it-in-yer-bag portable addon for Traktor users, both on PC and Mac, but also for Traktor DJ on iOS.
Fully compatible with all of the versions of Traktor, this unit is very similar to the Traktor S2 mixer section. Featuring the same faders and knobs as the S2 and S4, this really opens up the use of iOS Traktor App for iMac and iPhone (yes, it is even reported to work with iPhone too!) “more than a bit of fun messing about” usage. Not only does it give you a true stereo output and stereo headphone cue for iOS, it’s also an ultra-portable solution to anyone with its partner X1 or F1 controller for PC and Mac.
http://www.native-instruments.com/en/products/traktor/dj-mixer/traktor-kontrol-z1/