 The Index Solution is contained within a spray system that is activated by an intruder detection unit, similar to a burglar alarm, and marks the intruder with a spray, which the police locate using a black (UV) light.The "Indsol Tracer" variant is a polymer emulsion that blends different chemical agents according to a binary code allowing 10 billion different possibilities, as stated by the company.The "SmartWater Instant" variant consists mainly of a copolymer of vinyl acetate in isopropyl alcohol.