Where does the "Outlet" go on aftermarket coolant overflow tanks? I really don't know

[MustangLX-5.0]

I am installing the dual Contour fan setup. Just ordered a Hayden dual relay/controller. But I also need a different coolant overflow tank since the stock won't fit the fan. I am looking at dozens of different tanks. My question is, where does the "Outlet" go on these tanks. they have inlet and outlet. The stock tank only has one hose, but why do these have 2? I know one goes to the radiator, where does the other go? Do I need recirculating ? Sorry, I don't know what to look for here.

 

[MustangLX-5.0]

Any suggestions? I want to buy this with the fan controller so I can get it all done at once. What would you recommend out of this list at Summit Racing? Overflow Tanks - SummitRacing.com

Or are there other choices I could use? I'm not sure where to mount the square looking tanks.

EDIT ---- Never mind on the link. I just found those are direct replacement tanks. Looking at a lot of the other ones though, I found most have outlet connectors on them as well as inlet. I am not looking for just a bottle for holding fluid, but something that works like the factory one, but will fit some place with the Contour fan.

 

[HISSIN50]

You'd connect the overflow hose from the radiator-neck to the bottom of the new overflow.

The overflow needs a vent, and the top fitting can be used for that (the stock bottle is vented at the top as well).

 

[MustangLX-5.0]

So then the inlet is just used as a vent? Or is that used for adding coolant? Some of these don't even have caps on them. They are just one or two hoses connected and look like a nitrous bottle. What's a decent looking container that you'd recommend? I'm guessing something that would hold probably about 32 OZ worth. The 20 OZ containers seem to small and seem like they'd end up overfilling on long run times.

 

[Uber88GT]

I'm running my outlet to a small length of hose, about the length of the bottle and down to a clamp on the side of the inner fender, kinda under where the battery used to be

 

[Mustang5L5]

Connect to the bottom and leave top open as vent.

I am using the cheap summit house brand overflow on my car.