Shoulder harness guide bar is an absolute must to minimize compression injuries under high "G" loading. It works by properly positioning the harnesses and mounts behind and above the "B" pillars (option of "C" pillars on 944) at the "D" Ring mounting points. Confirm that your seat driving position does not put the front seat back past the "B" pillar point. If your front seat back does go past the "B" pillar point this bar will interfere. Retains use of stock harness. Fully adjustable for length because car widths do vary! No holes to drill. Easy in/out 1" diameter chrome moly tubing. Compact design finished in durable semi-gloss black powder coating to compliment your interior.