yea, the gravity bongs with the single hole in the bottom are awesome. you should get yours filtered man. i use just a regular 2 liter and change it out every once in awhile and i cut a hose the length of the bottle and it actually screws onto it the bottle cap and i have a ratchet piece with a screen sealed in the cap, and i put the hose into the bottle top, so when you raise it out of the water, it bubbles through the hose and when your done, just take out the hose, and inhale.