SMOK Nord 4 RPM Replacement Cartridge for your new SMOK Nord 4. This highly advanced pod system is compatible with two types of distinctly designed coils that each offers their very own vaping experience. The SMOK Nord 4 pods have a 2mL e-liquid capacity reservoir that is filled through a side mounted rubber plug. For your convenience, SMOKtech has made the filling hole a bit larger than other similar devices so you don’t have to worry about making a mess. Be sure to fully seal the rubber plug and let your Cotton wicks be fully saturated before each use to prevent leakage and burnt or dry hits.