The JFCB3700T4200WR229-13 from JQL Electronics is a Waveguide Filter with Frequency 3.7 to 4.2 GHz, Insertion Loss 0.5 to 1.5 dB, Operating Temperature -40 to 60 Degree C, Rejection 60 dB (Min). Tags: Band Pass. More details for JFCB3700T4200WR229-13 can be seen below.