Opal? is a practical workflow for the simultaneous detection of up to six tissue biomarkers plus nuclear counterstain within a single image. The method is similar to standard immunohistochemistry (IHC) and is accessible to many laboratories where standard IHC method development is performed. The Opal 4-Color Automation Immunohistochemistry Kit is designed for use on the Leica Biosystems BOND RX, and is configured and validated for imaging on the Vectra? and Mantra? systems. This kit contains reagents to stain 50-slides at the recommended dilution ratio.