Pizza screens are exactly what their name entails, a fine mesh pan on which you can bake pizza. Using a screen is the closest one will come to not using anything at all. The fine mesh surface offers little barrier for heat, so pizzas will cook faster than when in pans. As with all things pizza, you will want to find the right size pizza screen to suit your needs. You have the option of acquiring several screens of different sizes, one size to match each of your pizza offerings, or you can get only one size to accommodate your largest pizza and put the subsequent smaller pies on the bigger screens.
If you do decide to select several different sizes be sure to stay within the same brand. Even though all screens are practically the same, different manufacturing processes will create subtly different pizza screens. It is better to opt for uniformity so your 8 inch pizzas taste the same as your 19 inchers.