VAPO - E Liquid Unflavoured 18mg 60ml FreebaseFreebase is the purest form of nicotine liquid which is harsher than the salt but the nicotine effect is far more prominent and is primarily consumed by those who have been vaping for a very long time. Salts are freebase liquids mixed with benzoic acid which makes it a lot more palatable and feels smoother going down (better for those transitioning from smoking cigarettes).