CURT 6 sq. ft. Black Steel Roof Rack Cargo Carrier Extension Model 18124CURT 6 sq. ft. Black Steel Roof Rack Cargo Carrier Extension Model 18124 The CURT roof rack cargo carrier extension offers a convenient cargo solution and allows you to add an additional 6 sq. ft. of cargo space to your CURT roof rack cargo carrier (#18123 sold separately), allowing you to securely store large items outside the vehicle. Free up space and ensure a comfortable and organized interior for passengers and pets! With the CURT roof rack cargo