What is the difference between the different Thule roof bar systems?

What is the difference between the different Thule roof bar systems? thule t slot rack An adapter for fitting the Thule ProRide bike carrier directly into the t-track of some BMW and Renault original load bars thule fietsendrager slot It also features a new QuickAccess interface that allows smooth and easy installation and removal of accessories to the t-slot rack with all

thule fietsendrager slot T-slot for easy accessory installs; Equipped with T-tracks

thule t slot rack Your browser can't play this video Learn more Elevate FS Rack System and Thule Hull A T-slot for easy accessory installs; Equipped with T-tracks