3M(TM) Lead Foil Tape 420 Dark Silver, 19 in x 36 yd 6.8 mil 3M(TM) Lead Foil Tape 420 Dark Silver, lead foil backing with a green rubber adhesive and a clear, easy-release film liner. 3M(TM) Lead Foil Tape 420, linered tape used as a maskant in electroplating and as a moisture and radiation barrier in certain applications. Lead foil backing provides good conformability having electrically and thermally conductive properties. This linered tape can be easily die-cut into special sizes or shapes.