the one to fit the
Etrac/explorer series
(SUN RAY X-1 TARGET PROBE)
has to be professionally mounted to the upper rod,
so the cable runs inside it (part of the reason you'll
most likely pay close to $300
for a used one for the Etrac)
so odds are in order to get one, you will need to purchase an Etrac or explorer
with it on or get lucky someone will split it up.
ebay would be the most likely place to watch.
and it won't hurt to watch our classifieds just in case.
in all honesty, I had one for my first Explorer.
in order to use it properly I needed to lower me sensitivity drastically to
pinpoint. otherwise, at Full sensitivity it was like holding a ball of Lightening
and sticking it in the hole. The detection range went all the way up through the
probe wire, so there was no way to pinpoint the metal.
so if you like to hunt with Full sense Like me

You got this
till you turn it down
I'd still probably purchase another, if they were $50.00
in contrast, the S-1 on my sovereign was indispensable

one of the best investments I ever made.
I even wore the tip off the first one and bought a 2nd.