Alright bitches, I see all these post about how to make a grav, well they suck. I kinda see myself as a grav master, so yeah:

(1) Clear 3 Liter soda bottle, Sam's Club or Big Fizz works
(1) Utz Cheese Ball Container
(1) 7/8 in. Socket
(1) Screen

Cut the bottom off of your bottle on the bottom line and set aside. Take the cap off the bottle and drill a 1/2 in. hole in the center. Take a lighter and making sure you don't melt the threads, melt the hole just for a second or two, then push the socket through the hole. If you did it right there should be a perfect seal. The key to a good grav is no air getting into the bottle except through the socket. Now fill the cheese ball container up with water until it's right under the idk "spout" of the soda bottle. Put a screen in the socket. There you just made your first Mr. Utz gravity bong.

To use it you just brim the socket with some herb, screw the cap on, light and pull slow stopping about an inch above the bottom of the bottle, unscrew and suck in*. Do not push down on the bottle.... When you suck the smoke out of the bottle it will want to drop on it's own.

You don't just pull the bottle up at one constant speed you gotta read the hit, but I can't teach you that.

*When you go for the hit you want to put your top teeth on top of your bottom teeth and make your lips like your sucking through a straw. Your teeth will catch all the nasty resin that makes you hack and cough, aka shit tooth.

Thats all I can teach you about gravs enjoy...