The MR11-0018-20 from MAST Technologies is a Microwave Absorber with Frequency 18.0 GHz, Thickness 0.046 Inch/1.2 mm, Thickness 0.046 Inch, Thickness (mm) 1.2 mm, Operating Temperature -60 Degrees F to 375 Degrees F. Tags: Tuned Frequency Absorber. More details for MR11-0018-20 can be seen below.