How many reasons do you need to purchase this 8-inch plastic funnel? Imagine pouring your wort through that little opening in your carboy without it. Now imagine spray painting it silver, wrapping yourself in foil, and going out as the Tin-Man for Halloween.
The funnel DOES include a screen.

California Proposition 65

Proposition 65 Warning: This product contains chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm.