So I'm looking for a way to mount my antenna on the back of my vest but keep the radio up front for use.  

This does look promising.  

TCI MAST

Anyone know if it's water proof?  When I called the girl said that she thinks it's waterproof, but not submersible.  Wish I talked to someone with more of a definitive answer.

Any help on picking out what "MAST Cable Version" I need?  I have a Yaesu 8X-DR & Diamond SRH320A Antenna which I believe have SMA connectors correct?

Looking at that first part of the description it only mentions a handful of radios?  Will it work with mine?  It seems to only come with wire & antenna mount, no antenna.  While pricey, seems to be the only durable option.

I also found this 90* Connector, but apparently TCI doesn't make an SMA version, is there any other 90* SMA adapter on the market that would work with this TCI MAST?  It would be nice to help keep the wire end out of harms way.

Someone on a HAM board posted this: Opek AM-551

But the TCI MAST looks to be a better & more durable setup.

not to hijack but I'd like similar answers for the UV-5R+....

I bet I could make something similar for less than $64 though...

It looks like it has a BNC connector on it, and if so you'll need a BNC to SMA female adapter for the Baofeng.

This topic comes up about once a month. It is doable if you want it, however I have used that type of system first hand and thought it was more bother than what it's worth.

I think we know that all the cool guys point their antennas down.

I found an antenna that does that by the way.

DXE Link

$64 for a coax jumper?

Oh No not just a jumper but a Pouch as well

I need to start building and selling these $64 is a lot of money for what that really is.

But, it's tactical...

Tactical Monkey waste of cash.

I'm detecting your sarcasm, but really, the pouch is barely even a pouch. It doesn't protect the antenna; it doesn't even appear to protect the connector. It's barely a strap to hold the antenna in place, and I don't know if I would trust it to do that.

IF a person couldn't build one up just as good or better with their own know how or by asking here, then they probably ought to call the TCI, rather than order online, so they can explain what they have and what they want to make sure they get it right. Anyone capable of looking at those options and figuring out what will work for them could build one of better quality for less.

I don't see any info on what band(s) that thing is for.

It's not for any particular band, as it doesn't come with an antenna. It's literally a coax jumper, and a small nylon piece used to attach the antenna to your nylon.