This is a clear plug style carb cap made from quartz. This carb cap is meant to be used on terp slurpers, control towers, and similar bangers. It is meant ideally for bangers that have an OD of 16mm at the top. This cap has a large nub style handle for easy grabbing. These are way more ideal than the sticky round marbles that people usually use, that roll off the table and get your fingers sticky.