THIN: This thin crystal clear skin is used for overcoating the medium and thick skin if marking pens multiple layers are used. Medium: A soft and chewy adhesive backed material for any tying application. The medium crystal skin is used for general tying applications. It is stretchy, durable, waterproof and can be cut with any of our River Road Cutters. Ideal for minnow, crab, and scud patterns. Vendor: Hareline Dubbing