Not sure whether this has been put up before. Below is a source to purchase these male and female plugs on line from a company called Element 14.
The male plug as fitted to the waterproof headphones :-http://au.element14.com/amphenol-tuchel/12-08bmma-sl8001/m12-i-style-sensor-connector/dp/2254170?Ntt=12-08BMMA-SL8001
And the female plug as fitted to the body of the CTX:-http://au.element14.com/amphenol-tuchel/12-08bffa-sl8001/m12-i-style-sensor-connector/dp/2254169Note
that the male plug above does not come with the waterproofing external 0 ring. You will have to source the 0 ring which appears to be 12mm outside diameter, 10mm inside diameter and the wall thickness 1mm. These 0 rings should be available at any automotive bearing supplier.
The female plug appears to have the internal 0 ring (green in colour) fitted. If this plug was used as a replacement on the CTX body make sure the internal 0 ring is fitted to insure waterproofing. Although I wouldn't think the the user would replace the plug on the CTX body as they would have no way of pressure testing the control box for water-tightness after reassembling. Make sure that you are happy that the plug makes a waterproof seal when connected to the detector. I take no responsibility should it not.
I have purchased a female so I can make a short cable with the female plug on one end and a 6mm stereo plug on the other so I can connect my Underwater Grey Ghosts to the Minelab WM10 wireless receiver. I will only need to carry the one set of headphones (Grey Ghosts) for either application. I have checked with the Grey Ghost manufacturers and they say other CTX users have also made the same connecting cable for the WM10.
Hope this helps.