These are Minelabs ML 85 Low Latency wireless headphones that suit the equinox 700 and 900 series and the new X terra Pro.
Full Description below.
Minelab ML 85 headphones use wireless technology to deliver fast, higher quality audio than standard Bluetooth. This results in more precise and faster detection responses. They are compatible for use with MANTICORE, EQUINOX 900, EQUINOX 700 and X-TERRA PRO detectors.