Detector traces of nitrates, explosives or gunpowder

The On The Spot^TM detector is a card which detects gunpowder residues and traces of certain explosives including ammonium nitrate contained in explosives, fertilizers and related compounds. Side A of the detector is pressed onto the suspect surface, and then onto Side B of the detector. ADD a few droplets of the provided activator to the detector. Red spots will form on the initially beige card wherever tiny particles of gunpowder or explosives contacted it. The detection sensitivity is of the order of 10-9 gm of NOx. The color appears in 2-60 seconds at room temperature.