Salt NIC eliquids and ejuice operate much differently than free base nicotine. These salts form naturally in leaf tobacco and are considered to be a more stable form of nicotine than free base. 

Saltnic liquid is mostly used in Pod devices but not limited to pods, can also be used with mods with coils that are meant to be vaped using salt nic flavour ejuice and a very good alternative for people using regular tobacco cigarettes.