Abstract: Magnetizable particles ranging in size from 0.5 to 20 microns are dispersed in an insulating binder of thermosetting material to form a mixture in which such particles comprise approximately 90% of the weight of such mixture. The particles are either spherical or the mixture may be magnetizable material coated on spherical glass balls of micron size. The mixture is applied by painting or spraying to form a coating of approximately 40 mils or an otherwise metallic reflecting body or may be so applied to a sheet of flexible material which in turn is affixed to a metallic material otherwise exhibiting reflectivity for energy in the frequency range of 2 to 10 Ghz.