Concentrate Tools Carb stands for carburetor, and much like the carburetor under the hood of a car, they help to regulate airflow in a specific way. This can work in a number of ways, depending on the design of the carb cap. Carb caps are responsible for trapping that heat, and even adding more air to the oils, making them vaporize even more efficiently. The clear bubble carb cap is made to be used with Quartz Bangers and measures 2.25" long and 1" wide. Carb Cap Features: Size: 2.25" long | 1" wide Use With: Concentrates Bubble Design Works best with Quartz Bangers