 SmartWater comes in three variants, "Index Solutions", "Indsol Tracer" and "SmartWater Instant", which use different techniques to embed such a code.According to Phil Cleary, this allows "millions of chemical signatures" and is an identifier superior to genetic fingerprinting DNA.The "Index Solutions" variant is a water based solution containing low level additives, which are blended using a binary sequence to ensure uniqueness.