The MR11-0031-20 from MAST Technologies is a Microwave Absorber with Frequency 20.6 GHz, Thickness 0.043 Inch/1.1 mm, Thickness 0.043 Inch, Thickness (mm) 1.1 mm, Operating Temperature -60 Degrees F to 375 Degrees F. Tags: Tuned Frequency Absorber. More details for MR11-0031-20 can be seen below.