Convert a female joint into a male joint with this useful glass adapter. The sturdy attachment is available in both 14mm and 18mm sizes. A frosted ground glass finish anchors onto the J-Hook or water pipe with a flawless glass on glass seam. GRAV Labs delivers exquisite scientific quality from their Austin-based location. Each silhouette is precisely measured and made into an unbeatable attachment. The masterminds behind the Gravitron, Upline, and STAX collections are maximizing the amount of pleasure you can pull from each epic device with GRAV-approved accessories. These accessories allow for a mix-and-match variety of uses out every pipe -- swap around ash catchers, pre-coolers, bowl slides, and nails to suit your mood. This excellent glass adapter is easy to keep as crisp and clean as the day you unboxed it. Scientific glass refreshes with a just simple soak. That means more build-up in a maneuverable accessory rather than within the walls of your beloved water pipe.