The QWBF-3800-4200-45 from Qualwave is a Waveguide Filter with Frequency 3.8 to 4.2 GHz, Insertion Loss 0.3 dB, Operating Temperature -40 to 60 Degree C, Rejection -65 to -45 dB, Rejection Frequency 3.5 to 4.9 GHz. Tags: Band Pass. More details for QWBF-3800-4200-45 can be seen below.