This is a handy gadget to have in your kitchen as it handles tough meats and tenderizes them. I like to use it for chicken paillards which I like to be 1/4-1/2-inch thick.
I also use it when I make my Irish Cream Cheesecake With Mixed Berries. For the crust I press the crumbs into the pan using this metal gadget.
There are many different brands, some are flat and round like mine, and others have ridges underneath (obviously I would not use this kind for my cheesecake crust), some are plastic or metal, like mine. The brand I have is Rowoco, made in Italy.

