I think they originated on semi-trucks and then cars of the 1950's. Probably because of the large diameter steering wheels and lack of power steering. They are helpful on boats but not sure if they will help much on a new jeep. You can probably get one at a truckstop on most major interstates...
Only 3 months old off of my new jeep was only on for 2 months. Is black textured 4 door top with freedom panels and all mounting hardware. Has tinted windows and is in perfect condition. Also includes freedom panel storage bag. I am located in Panama City Beach Florida and will help you install...
You can install an attic wall mount ventilation fan in your wall and wire it to a manual switch and just turn it on when you feel you need it. When its off the louvers close so you wont loose to much heat.. I used them in my hot garage during the summer months. Good luck.