Water Tight RTD source, ebay, Auber, ?

Well I did my first brew on the electric brewery last week only to find a short in my type K thermo. I have read that RTD is perferred over Type K so this gives me a chance to upgrade. I'm running inline with HEX so I only need 2"-2.5" probe 1/4" or 1/2" NPT.

Auber sells this for just over $30 with shipping, but then I notice ones on ebay that are under $10. How does one determine if they are water tight. If not could one just use a compression with o-rings? I plan on wiring to an XLR connector so I don't need fancy ends.

If anyone has any input feel free to share.

I can say that the Auber one is definitely water right and works well...though I had trouble sourcing a threaded nut that'd lock it down from the inside, should have just purchased the one they sell specifically for it at the same time.

I've been doing a lot of shopping myself. I've decided to go with Kal's premade couple. Granted its expensive. But man is it sexy.

these are both water-tight.

http://www.ebay.com/itm/250867592524?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648

http://www.ebay.com/itm/RTD-PT100-T...092?pt=LH_DefaultDomain_0&hash=item3a53cc96fc

I bought the cheaper one at first, but I move my HEX coil around a lot and the connections started to get flakey, so I bought the burly ass one after that and love it.

First one is 1/4" NPT, second one is 1/2" NPT.

I half-ass fixed the cheaper one and use it now in an electric smoker.