Plate, Pet Cooling Board, Dish, Bread Kneading Board, Audio Board, Base

I received this 10 years ago but didn't know what to use it for, so I kept it stored away without using it.
Searching online, it seems to have various uses such as a cooling plate for pets, a dish, a bread kneading board, an audio board, a base, and more.
I weighed it on a human scale, and it was 6.5 kg.
Please check the photos for scratches and dirt.
I try to inspect carefully, but I apologize if I have overlooked anything.

After checking the photos, please consider and purchase with the understanding that there may be oversights due to amateur inspection and that it has been stored at home.
It will be wrapped in cushioning material and shipped in a cardboard box.