3-Amino-9-Ethylcarbazole (AEC) is a widely used chromogen for immunohistochemical staining and immunoblotting. AEC produces a red end product that is soluble in alcohol and must be used with an aqueous counterstain and mounting media. This product is available in a two-component form consisting of a liquid, refrigerator-stable AEC Chromogen and AEC Substrate. Each component is individually stable for 18 months from the date of manufacture.