Two Step Polymer HRP is a polyclonal secondary antibody marked with the HRP enzyme used for immunohistochemical staining of samples fixed with formalin or glyoxal and embedded in paraffin blocks. It consists of two components. The technology of polymerized secondary antibody that is conjugated with peroxidase enables bypassing of endogenous biotin and its background signal. Two Step Polymer HRP is effective with mouse and rabbit primary antibodies. It is available in two sizes, for 250 tests (25 mL) and for 1250 tests (125 mL).