You get the choice of a carb or a slider. All they do is allow fresh air to enter the bong and help you clear it.

And the other one.
MuddinPede Reviewed by MuddinPede on . 2 Homemade Bong Questions Hello. I am interested in making my first homemade bong, and I have a few questions. 1. Does the bong need to have a carb, or do I get the choice between the carb and a slider? (I understand how to use each, but i don't really understand what it actually does.) 2. If the bowl piece were connected to an empty pen (this is where the smoke will be drawn into the bottle), should this opening in the pen be under the water? Any other tips would be great. Thanks. Rating: 5