You can use this connector to make your own waterproof headphones for use with Garrett AT Pro international metal detector.
This connector also need two 14x11x2,5mm o-rings and a cable gland which you can both buy at ebay. There are also two pins required (MS3193) which are not easy to buy.
I'm still looking for cheap replacement pins, male and female. Pin diameter is 1mm and should be at least 10mm long.
I put two 13,5kohm resistors parrallel to reduce the volume because you will get ear damage otherwise. You can also take one 6kohm resistor.
You can also use an extension cable with built-in volume control
I used this spring type cable combined with the resistors, see images
O-rings 14mmx11mmx1.5mm, you need at least two of them
You can also buy cheap lightweight waterproof in-ear headphones for a complete assembly