Aclass This is a microphone/speaker conversion adapter for PS4 controllers. It converts a 3.5mm 4-pole plug to 3.5mm 3-pole plugs for headphone output and microphone input. I bought this to record the line output of my electronic piano on my smartphone, but it only worked successfully about once every few times due to compatibility issues with the smartphone, so I'm selling it. It's almost new, but part of the packaging is torn.