They're adapters from car-speaker-adapters.com. They're made from PVC and come in several varieties for different speaker sizes. I added a little foam on the back to prevent rattling, but they're relatively cheap and easy to install.

 

That looks like a ky plate, I'm in ky also, how's the passenger fender look? I'm needing one for my car.

 

Howdy fellow Kentuckian. Unfortunately, the fender didn't fare well. The impact from the light pole pushed the back part of it inwards, which was further crushed by the door when the car hit the culvert.

 

What part of ky are you in? I'm in Richmond, I just bought my 2000 gs300 last week out of Louisville on Craigslist and the passenger fender is rusted a bit, I'll find one in black eventually.

 

I'm over in Lexington. Even if the fender wasn't damaged, it still had its flaws in terms of rock chips and less than perfect touchups. I'm sure you can find a fender around somewhere, but you might have to resort to having one shipped to you.