I have a pair of these cross bars that attach to your roof rack, typically required for Roof Top Tents. We are selling our tent so we will no longer need these. They have been on our rack for about 4 years. Some of the hardware is a little rusty, so you may need some new bolts otherwise they are in good shape. 

They are the medium sized crossbars from BajaRack's website. 40" long. 
https://bajarack.com/products/universal-roof-rack-cross-bars-medium

Make sure you know they are compatible with your rack before reaching out. I only know that they are compatible with BajaRack's tubing and mesh flooring. Since they are universal I'm sure you could get them to work with a variety of roof racks.

$325 to buy them brand new.

Selling for $175 (price is firm)

Cash or Venmo
Message with any questions.