2016 TRD Sport bed part question

Quick question...what’s the bar located on the top of the bed right below the rear window called/used for? Looking to replace it. Thanks in advance.

 

Hard to say without photos OP.

 

There’s the header rail that sits even with the bed sides. Then below that there’s the utility t slot rail that didn’t come on the 3rd Gen but you can buy it, lines up with the two rails on each side.

If you’re replacing it because the paint is coming off, you can just paint it with a black rattle can, many owners have.

 

I was curious also why the paint is coming of on it. I guess another quality issue.

 

Header rail. Thank you!...yeah my paint started coming off the first year.

 

I had the same issue... plastic dipped mine. Holding up well.