ETS-Lindgren’s Rantec brand High Power Microwave Absorber is fabricated from space-age high temperature materials. The pyramidal-shaped substrate is coated with a conductive polyimide resin film, the highest temperature polymer available. This resin withstands short-term exposures to 482.2 ° C (900 ° F).

The substrate used is a nylon honeycomb material, which is stable up to a temperature of 343.3 ° C (650 ° F). Due to the honeycomb structure and high temperature materials used, "pump-down" for high vacuum applications is rapid with low outgassing.
The flammability of HP Series Absorber is substantially lower than for conventional microwave absorbers, the material being quite difficult to ignite. If ignited, the EHP HP Series Absorber will self-extinguish quickly after removal of the ignition source.