A lead foil backing combined with a crude rubber adhesive with a white, easy release film liner. No. 420 is a good conductor of electrical current and has good thermal properties. Very conformable for use in electroplating and hardchrome plating, radiation barriers and chemical milling. Good thermal properties and will perform over a wide variety of temperature conditions (-55°C to 105°C). Has been used at higher temperatures for shorter durations. Applications ideas: Electroplating. Radiaton barrier. Moisture barrier.Chemical milling. X-ray plate masking. Maskout during paint stripping. Add weight (balance) to equipment parts (golf clubs, tennis rackets, etc.).