18mm Zob Glass Replacement bong slides. These are the same high-quality slides that come with each Zob Glass Bong, Bubbler, or Water Pipe. Each replacement slide features a one-hole push bowl that is the perfect size for smoking flowers and is made from extra-thick boro glass. Each 18mm Zob Slide and fits most standard 18mm female bong, bubbler, or rig joints. Attached to the herb bowl is a wide Maria-style handle for easy handling and to prevent the glass slide from rolling unexpectedly.