The vapor path of the AroMed 4.0 Vaporizer is supposed to be a one-way street. But inexperienced desktop vape users sometimes blow vapor back down the whip tube, harming the heating element. The AroMed Check Valve protects the heating element by ensuring vapor travels in one direction--outward. The AroMed Check Valve helps you avoid costly repairs, and delivers fuller hits from the AroMed 4.0 vaporizer. Easy to use, and built tough with quality materials, the AroMed Check Valve is a must-have tool for beginners.