This is a very effective modification and acts as an ACTUAL brace stiffening the rear chassis of the Z car. Its superior in design to the Typical inexpensive (hinged braces that bolt together) that serve more of a cosmetic purpose then an actual performance one. These cars are now over 40 years old and with suspension upgrades (i.e. stiffer shocks and springs) it will only be a matter of time until the chassis starts popping the old spot welds and compromising the integrity of the monocoque design. This bar installs fairly easily and will give you a NOTICABLE difference in chassis strengthening. Not only will this strengthen the chassis and reduce flex between the rear towers, it also gives you a sturdy mounting location for a Camera Mount. The O.D. of the Bar is 1.5″. It comes powder coated in a Black Wrinkle finish. This is only designed for the 2 seater model at this point.