i dont know how this works and wats it called, its to hold the frame inttack

 

Looks to be a tension rod brace.

 

k thnx rep

 

It's Called an Adjustable FLOOR BAR or CHASSIS BRACE.

It mounts in the back of your front seats by using the Bolts that hold the bottom of your seatbelts in place. This helps maintain rigidness in the vehicle and is fully adjustable
It does actually work!!! I had one in My DC back in the day made by Do Luck, They are the Originator of this design.

 

I have one they work p.s what up jeff

 

thanks bro rep'd