Construction of electronic cigarettes Wikipedia Disposable vape, just three components but what it bugs me how does it know when it's empty. Led flashes when no juice is left but how? What makes led flash? Vape Juice Storage Tips: How to Store Your e Liquid Properly? MYTH : There's only THC or nicotine in the juice of my vape, no other harmful chemicals. FACT : Vapes are an aerosol. Certain chemicals have to be in any