Carb caps are covers for your banger or nail. They help trap heat once your dab has been dropped onto the nail. Carb caps restrict airflow and trap heat around domeless nails or bangers, allowing the cannabis concentrate to vaporize at a lower temperature. In turn this preserves the quality and flavor of the concentrate. The term carb cap comes from the word carburetor because a carb cap is to a dabbing rig what a carburetor is to a car. Just like a carburetor controls the airflow, and, as a result, the pressure around an engine, a carb cap controls the airflow and, as a result, the pressure around a dab.