This kit connects a phone bluetooth audio adapter directly to your car stereo's CD changer port. This results in better audio quality, allows you to use your steering wheel media controls to skip tracks, and avoids having to find an empty radio band to tune an FM bluetooth audio adapter (which gets very annoying on longer road trips).
This kit also supports phone calls and comes with a microphone that you can wire up the A-pillar of your vehicle.
I had this kit installed on my 2005 Toyota Camry LE for a couple of months before it got into an accident and was totaled. There was no damage to the stereo system area so I took this kit out. I love this company's stuff so much I bought an identical kit for my new (to me) car.
More information and installation instructions can be found on their website here: https://www.gtacarkits.com/product/toyota-camry-2005-2006-iphone-aux-kit/
Please note it appears that "If your Toyota Camry stereo model starts with AD letters (e.g. AD6806), our kit would not support it. The model name usually is displayed on the front panel of the radio."