The MR31-0004-20 from MAST Technologies is a Microwave Absorber with Frequency 5 to 8 GHz, Thickness 0.05 Inch/1.3 mm, Thickness 0.05 Inch, Thickness (mm) 1.3 mm, Operating Temperature -60 Degrees F to 375 Degrees F. Tags: Surface Wave Absorber. More details for MR31-0004-20 can be seen below.