A pizza screen is what many commercial pizzerias use to bake their pizzas. Like a perforated pizza pan, it is designed to allow the heated air of the oven to make more contact with the bottom of the pizza, giving you a crispy golden brown crust. A screen doesn't need to be preheated like a pizza stone, so you can get your pizza in the oven sooner.
Pizza screens should be seasoned before use. Simply rub them all over with some vegetable oil and place them in a 400 degree oven for 30 minutes. Then turn your oven off and let the screens cool in the oven before removing them. Over time and with repeated use, your screens with darken, allowing for even better browning of your pizza.