18mm Zob Glass Replacement bong slides. These are the same high-quality slides that comes 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 flower 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.