3,3' Diaminobenzidine (DAB) is the most widely used chromogen for IHC staining.  In the presence of peroxidase, a common label for antibodies, DAB produces a brown precipitate that is insoluble in alcohol or xylene. This chromogen kit produces a crispy brown color at the site of labeled antibodies in tissue sections, bringing superior contrast with the light blue nuclear hematoxylin counterstain in the cells. The working DAB solution is stable up to six hours, being ideal for manual and automated staining processes.