The Traktor Kontrol S4 Mk1 is a double deck controller designed for DJs, with two phono inputs and one mic input. Unfortunately, this specific unit has a fault on channel B and bleeds through, also an in intermittent crackle and slight bleed on channel D. Despite this issue, the Traktor unit plays fine otherwise and is in good condition and has been been stored in a flight case. Would make a great controller for someone with a bit of electrical knowhow, I have seen the faders available on eBay and online.
eBay