Chip Guards (Like Mud Flaps)

Was doing my annual cleaning of my 99 Max last weekend. Noticed a lot of paint chips marks behind the wheels on the lower doors and under the body. On the way to work today, I followed a 03 Max and it had sometype of guard behind each wheel to stop the rocks that kick up. It looked like it was installed over the standard body and they did extend out to width of the wheel.

My Nissian dealer doesn't have a clue, but thats not strange. Does anyone know what these are called and if they are available for a 99. It looks like a neat idea, I don't like the mud flaps but I do like these devices.

Thanks.