3M Circuit Plating Tape 1280 with polyester film used for PCB masking tape or other high temperature applications. Red. 3.6 mil thick."Halogen Free" refers to the International Electrochemical Commission’s Definition, IEC 61249-2-21, which sets the limits of: 900 ppm maximum chlorine; 900 ppm maximum bromine; 1500 ppm maximum total halogens