Putting Electronic Cigarettes to the Test (image) Fraunhofer-Gesellschaft Share Print E-Mail Caption E-cigarettes come in many different guises, yet they all have one thing in common: they only emit vapor when switched on. Credit © Fraunhofer WKI Usage Restrictions The picture may be used for editorial purposes only. It is protected by copyright. The use is free of charge if the reference is mentioned. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.