HEAVY DUTY CONSTRUCTION The racks are made of 22mm diameter and 1.5mm thick steel tube, 8.5 "widening design, stronger than else. Black Powder-Coated Steel for Durability & Rust Prevention Plus Long-Lasting, can resist all weather condition and use for a long life.150 Lbs Tested, easy and safe for your transport. FOLDING AND ERGONOMIC DESIGN Ergonomic quick release design, more easily to fold and raise the racks than others. Racks can be folded flat when not in use, get better clearance to drive your car into garage and not have to remove. REDUCE SCRATCH DESIGN Foam Padding and Rubber Pedal design to reduce scratch of your kayak and prevent the canoe or kayak from rubbing. UNIVERSAL MOUNTING DESIGN Compatible with most crossbars,such as square, factory and aerodynamic crossbars Except the round bar.