Nails are available in a variety of sizes and both male and female joints. Universal nails are also available, Universal nails can be used with both male and female connections that are 10 mm, 14 mm and 18 mm. They also come in a variety of materials, such as quartz, titanium, Stainless, and ceramic! 18mm Female Titanium Banger Style 10mm Female Ceramic Domeless Nail Universal Titanium Nail with Attached Carb Cap Universal Titanium Domeless Quartz Nail for 18mm Male 18/14mm Universal Domeless Nail Titanium Nail for 18mm Male Universal Anodized Aluminum with Quartz Dish for E-Nails 18/14mm Female Ceramic Domeless Nail Titanium Nail for 14mm Male Quartz Nail for 10mm Male 18/14mm Universal Domeless Nail Quartz Nail for 14mm Male Titanium Nail for 10mm Male