BEHRINGER INFINIUM X1 OPTICAL DJ FADER Upgrade your DDM4000 DJ mixer with the X1 INFINIUM Optical Fader. Its patented and contact-free optical technology means the X1 will see you through countless performances, all while delivering a truly analog feel and touch. The X1 is fully adjustable, allowing you to set the friction to your own personal preference. Complete installation instructions and a dedicated toolkit are provided for your convenience. Start enjoying the ultimate in high-precision, custom-tailored performance with the fantastic X1 INFINIUM OPTICAL FADER! Ultra-long life through contact-free optical technology Ultra-high digital precision (128 positions) Truly analog touch and feel Fully adjustable friction with contact-free magnet