Whatman™ felt-tipped membrane filter marking pen. For marking nitrocellulose and nylon transfers. This membrane marking pen is a high-xylene, felt-tipped marker that permanently writes on nitrocellulose and nylon membranes used in standard transfer procedures. This indispensable tool ensures easy identification and orientation of gel transfers, colony and plaque lifts, and Western blots, even when the membrane is damp. It is compatible with hybridization and incubation buffers. An ideal marking pen for keeping records of transfers. 10/Pack.