The brainwave synchronizer that claims to induce "state of mood lift, euphoria, sedation, and hallucination" that has parents, educators and lawmakers worried can be explained by what’s called the binaural beats. Here, two constant tones in slightly different frequencies heard from each ear cause the brain to perceive the sound in a brand new frequency. These songs, or "doses," are said to be the healthy alternative to recreational and illegal drugs. But critics fear that this may become the gateway drug for many. Credit: NMA World Edition