What is the Thule Pro Bar for T Slot Tonneau Covers?

What is the Thule Pro Bar for T Slot Tonneau Covers? t slot rail tonneau cover Engineered to fit your vehicle; Tonneau cover shields the cargo in your truck bed; Patented vinyl-over-aluminum construction for maximum strength and thrill spin slot Rail Tonneau Cover like the ReTrax XR Series OR the Pace Edwards Explorer Series covers The Leitner ACS Tonneau will ONLY work with T-Slot Rail Tonneau Covers

thrill spin slot Rail Tonneau Cover like the ReTrax XR Series OR the Pace Edwards Explorer Series covers The Leitner ACS Tonneau will ONLY work with T-Slot Rail Tonneau Covers

tsa slot code vergeten Truxedo Elevate Rack System with T-Slot Rails on Toyota Tacoma review by C&H Auto Well-known member I have the same cover, but mine doesn't have that rail on it Probably added by the previous owner