Presumptive test designed to identify the presence of all forms of Heroin (White, Brown and Black tar). Break and agitate the first ampoule for 30 seconds. A Green color will slowly develop as you agitate the test after breakage of the 2nd ampoule. ODV 924 NarcoPouch Mecke’s Modified Reagent (Heroin) odv-924Regular price: $29.99Sale price: $21.30 Copyright 2012 Police Supply Online providing Police Equipment to over 300 Police, Federal & Military Law Enforcement Agencies around the world.