Dielectric Properties refers to the voltage breakdown rating of the dielectric pad, typically tested per ASTM D149 and measured in kVAC. This is an average of 5 tests of the materials resistance to having voltage penetrate through the pad. It is therefore possible to have 1 or more results well below the voltage breakdown rating specification and yet still have the average of the 5 tests material that passes the specification limit. This table here is based on voltage breakdown of material at normal humidity conditions, typically 40% to 50% relative humidity.