The Aqua-Hold PAP Pen draws a liquid repellent barrier around a section of tissue. Used like a paint pen, you just draw a well on a slide. The barrier creates the proper surface tension to hold aqueous solutions such as costly antibody and other valuable specimens. After application, the barrier material is insoluble in alcohol and acetone but can be removed after staining with xylene. Each pen holds 13ml of long-lasting material, making hundreds of wells. Red tint distinguishes the well drawing on the slide to easily view.