The LS20-310 from Withwave is a Microwave Absorber with Frequency DC to 10 GHz, Thickness 0.13 Inch/3.1 mm, Thickness 0.13 Inch, Thickness (mm) 3.1 mm, Resistance 1 x 10^6 Ohms. Tags: Cavity Resonance Absorber. More details for LS20-310 can be seen below.