What output am I looking for. Subwoofer

[Reissv1234]

When I buy a stereo for my car on the specifications what am I looking for in terms of it being capable to hook up to my sub woofer

 

[CrippsCorner]

I think mine literally has a connection called Sub Out? I'm sure 99% of aftermarket headunits will be able to do it.

 

[Ol’ Tarby]

"Pre-out" is what you need