To reduce the radar cross section at microwave frequencies. it is necessary to implement electromagnetic (EM) absorbing devices/materials to decrease the strength of reflected waves. In addition. EM absorbers also find their applications at higher spectrum such as THz and optical frequencies. https://www.spidertattooz.com/OPI-GelColor-The-Color-That-Keeps-On-Giving-0-5-oz-HPJ07-p22791/