Different from normal base liquids. 

Nicotine salt Eliquids are the most efficient way to deliver nicotine to your body. A large number of vaper's say they find that nic salts deliver a more satisfying experience, saying Eliquid with nicotine salt is easier to inhale thanks to its bio-compatibility.

Because nic salts contain nicotine the uk tobacco laws for Eliquids have limited the bottle sizes to a maximum of 10ml and the maximum strength to 20mg