What size is my bong joint: 10, 14 or 18mm?

Almost every water pipe on the market uses one of three joint sizes: 10, 14 or 18 millimeters, each in male or female. The counter trick for identifying yours is a dime: it is about 18 mm across, so it roughly matches an 18 mm opening, sits halfway proud on a 14, and will not begin to enter a 10.

The measurement is the diameter of the ground-glass connection, and gender describes which way it nests: a male joint slides into a female one. The rule that confuses everyone is that accessories take the opposite gender of the piece; a bong with a female 14 mm joint takes male 14 mm bowls. Read the piece, then buy the opposite.

Size tracks the scale of the piece. Compact pieces and pen-style rigs run 10 mm, the everyday mid-size bong runs 14 mm, and big-volume tubes run 18 mm, where the wider bore moves more air per pull. This is why a replacement bowl is never just "a bowl": it is a gendered size, and two of the six combinations look nearly identical at arm's length.

When the sizes do not match, adapters bridge them: a 14-to-18 expander or an 18-to-14 reducer costs little and rescues an otherwise orphaned bowl or ash catcher. The one thing adapters cannot fix is a cracked ground joint, since the seal depends on that frosted taper mating cleanly.

If you are unsure, bring the piece in, or even a photo with a dime in frame, and any of our counters can size it on sight. Replacement bowls, downstems and adapters in all the standard sizes live on the glass shelves at every shop.

This is general information, not medical or legal advice. Product labels and current law outrank anything on this page. Everything we sell is for adults 21 and over, with valid ID checked every time.