The PAP Pen draws thin film-like barriers on microscope slides. This barrier creates the proper surface tension to hold antibody solutions and other specimens within a target area. The PAP Pen releases fluid in precise amounts to provide optimum surface tension. This eliminates the possibility of flooding the slide.

The PAP Pen can be effectively used for immunostaining by the PAP (peroxidase-Antiperoxidase), ABC, frozen section and fluorescent antibodies methods. If the frozen section method is used, two specimens are easily separated by applying two individual circles on the same slide. The PAP Pen contains a special water repellent formulation that is insoluble in alcohol and acetone. It can be removed with xylene if desired after staining procedures are completed.