This 4 point roll bar has a bolt-in diagonal cross brace and harness mount tube. Autopower will select tube size and type for your needs. Race roll bars are made with 1.750 x .120 dom steel. Cars weighing more than 3500 lbs. Use 2 x 120 erw steel. 4 point mounting with welded diagonal crossbrace. All necessary installation and mounting hardware with back-up plates is included. Optional bolt-in diagonal and harness tube can be ordered for this roll bar. Pictured with adjustable seat brace not included. Quick and easy installation and removal of these race roll bar options allows for access to the back seat for street use.