The AT-HPF-81-12 from AT Microwave is a Waveguide Filter with Frequency 81 to 110 GHz, Insertion Loss -2.5 to -1 dB, Operating Temperature -40 to 85 Degree C, Rejection -40 to -35 dBc, Rejection Frequency DC to 78 GHz. Tags: High Pass. More details for AT-HPF-81-12 can be seen below.