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

Thule ProBar Rack for Tonneau Cover w T-Slot Channel Rails thule t slot RHRSWAG #Thule #TonneauRack Upgrade your pickup truck equipped with a tonneau that has thule frameklem met slot Full T-Slot Mount Compatibility; Max Weight of up to 165–330 lbs Attaches to Crossbars or Directly to SkyLine and TimberLine Towers with Adapters (Both Kits

thule t slot bolts Review of Thule PowerClick Cargo Box T-Track Adapter Kit