Nicotine Salt, also known as Nic Salt, is a different type of processed nicotine vs the regular "freebase" nicotine.

Nicotine salt e-liquid is much easier to inhale than regular e-liquid due to its biocompatibility. The vape is less harsh on the throat and allows vapers to use stronger e-liquids. It's this ability to inhale more nicotine per puff that makes nic salts more satisfying for some vapers as it more closely mimics the nicotine found in a cigarette.