Grav Labs 14.5mm to 18.8mm Male Angled Expansion Glass Adapter

That cool ash catcher doesn't fit your piece?  Convert the joints on your piece easily with the Grav expansion adapter. 

These adapters are designed to increase the diameter of a joint, to make your favorite water piece compatible with larger accessories.  This glass adapter will convert a 14.5mm female joint into a 18.8mm male, but also change the angle from 45° to 90°, which makes it great for your beakers and straight tubes with an angled joint.