There are numerous attachments that can improve your water pipe's functionality. The problem is they do not always come in the necessary size and gender to fit your set-up. The 14mm Female to 18mm Female Adapter allows you to take any 14mm or 18mm male jointed rig and give it a female joint. One end is a 14mm female and the other is an 18mm female. This means it can fit 14mm and 18mm male jointed water pipes. Use a 14mm or 18mm male bowl and now you can smoke dry herbs out of your rig. Now you can just switch attachments and not entire bongs when you want to change up what you are smoking.