This is a used David Clark H10-40 aviation headset, which was refurbished by David Clark in 2014. (I have all manufacturer's repair paperwork). At that time, the microphone, cord, jacks, gel ear pads, and filters were all replaced. This is a standard dual plug headset. I have used it approximately a dozen times since then. This headset works perfectly! It has the volume control knob on the left ear cup, which controls the volume for both ear cups simultaneously. There are a few small marks and scratches on the ear cups from normal use.