Don't know how deep your nail should be in your dab rig? With Dank Tools' adjustable titanium nail, you can move the middle notch up or down to your desired height. This dab nail fits male 18mm joints and should be paired with an 18mm female dome. All three parts, the cup, counter weight, and height adjustment fins, screw off the nail for the easiest possible cleaning process. This is a strong, clean, durable dab nail that can last in your favorite dab rig for awhile.