im quite surprised at all the ridiculous suggestions in this thread... I by no means consider myself a cannabis connoisseur, but Ive only used a screen in a glass piece once, besides my bubbler, which has an abnormally large hole in the bottom, it's like 3/16" or 1/4" across, and it was because I was smoking nothing but keif and leftover stuff from the bottom of my grinder, I usually just put a big enough nug to not fall through at the bottom and pack around that to fill up the bowl in my dry pieces. If you have anything other than pure shake, a screen isnt really necessary in almost any glass piece.