All carb cap concentrate accories from AllGlass.com
What a carb cap does is create a chamber with restricted airflow for your concentrates to vaporize within. Most carb caps have a single hole which helps to create a lower stream of airflow allowing to trap the heat in a vortex to continuously vaporize oils at a lower temperature
Like nails, carb caps can be made of either titanium, ceramic, glass or quartz. The type you choose depends on personal preference since they all function the same for the most part.