A Cocktail Napkin Could Soon Detect Drugs in Your Drink With this new product, checking drinks for known date-rape drugs could be as easy as wiping a drip off your hand.

Kno-Nap isn't on sale yet, though when it is, it will cost about the same as a regular napkin. But Sherman doesn't want individual patrons to have to worry about carrying their own Kno-Naps around.