It is compatible with Hifiman HE400S / HE-400I ( old version with both 2.5mm plug) / HE560 / HE-350 / HE1000 / HE1000 V2 / AudioQuest NightHawk headphones. this cable has Dual 2.5mm male that be putted into headhone plug, it only fit the Hifiman headphones with both 2.5mm plug, it doesn't fit the HIFIMAN 4xx and it doesn't fit latest version of HE400i that with both 3.5mm plug.
eBay