Hindsight is now actually 20/20
You're walking down the street at night and you hear something moving behind you. You're sure it's a werewolf, but you know if you turn your head, it will maul you. Well, these plastic See Behind You Glasses have mirrors on the inside of the lens that let you see what's going on behind you at all times. Great for casing out joints, seeing who is approaching your cubicle and watching out for ninjas. Also great for spotting: muggers, nihilists, baseball furies, minotaurs, angry grandparents, that one guy you're trying to avoid, Zygons, close talkers, Carrot Top and Draco Malfoy.