Back in 2016, Digiflavor brought MTL to the masses with the original Siren, one of the first affordable MTL rebuildables on the market. Now in its fourth installment, the Siren is still a damn good vape! The Siren V4 is 22 mm in diameter, holds 2 mL of juice, and comes with the line’s signature raised GTA deck and full airflow adjustability.