Hard Dog Bolt-In Door Bars are designed specifically to stiffen the chassis of your Mx5. A torsionally stiff chassis will keep a more even load on all wheels to improve traction. The stiffer the chassis, the more likely the vehicle is to have even weight distribution on all tires which is favourable to cornering and superior handling. The door bars are easily installed in all '90-2005 model Mx5s in conjunction with any version Hard Dog roll bar with minimal interference for normal use of the car. Constructed of high quality 1.5" diameter x .120" wall DOM tubing and finished in black powder coated. Hardware included.