The Black Top Cap is an optional extra for the TRVP V2 Blueprint Atomizer for added stealth and style. It does get warmer than the plain version but with the heat sink on the base of the atomizer and the stock plastic or aftermarket glass mouthpiece we've not found this to be an issue. The top cap looks especially stylish when used with an AVS Vortex Airflow Adapter with Glass or Black Drip Tip!