The TWFCB-921M04-C04M50-N03 from Techniwave is a Band Pass Filter with Frequency 919 to 923 MHz, Bandwidth 4 MHz, Center Frequency 921 MHz, Insertion Loss 4.8 to 7 dB, Upper Rejection 50 to 70 dB @ 925 MHz, 927 MHz. Tags: Module with Connectors. More details for TWFCB-921M04-C04M50-N03 can be seen below.