The Nord 4 Pods from SMOK are empty replacement cartridges, designed for the SMOK Nord 4 vape kit. Featuring a 4.5mL vape juice capacity, they are available in either the RPM pod or the RPM 2 pods and are compatible with their respective coil families, the RPM coils and RPM 2 coils. Both coil families have capabilities for regular vape juice as well as stronger nic salts, so whatever your preference, the choice is yours! SMOK Nord 4 RPM Pod Spec: 4.5mL Liquid Capacity RPM Coil Compatibility Plug 'n' Play Coil Installation Magnetic Pod Connection SMOK Nord 4 RPM 2 Pod Spec: 4.5mL Liquid Capacity RPM 2 Coil Compatibility Plug 'n' Play Coil Installation Magnetic Pod Connection