Protech's core materials are formulated to efficiently attenuate portions of the photon spectrum and limit “gaps” in protection by blending x-ray protective elements. For example, Antimony and barium provide more efficient attenuation of the photon spectrum below the K-edge window of lead (35 - 88 kV). While higher Z elements tungsten, bismuth and lead are more efficient for stopping higher energy radiation (>9/88 kV), and also cover the K-edge fluorescence window of antimony (< 35 kV).