Rainbow Swirl Bubble Carb Cap

The bubble shape provides a tight seal with the silicone collar it rests on. 

When you use this carb cap, you'll get excellent vapor production and efficiency. There will also be less concentrate wasted after you vape thanks to the directional airflow control this carb cap provides you with.

This worked glass carb cap made of boro glass is a real looker with its colorful rainbow swirl design.