The QLF-3870-30 from Qualwave is a Low Pass RF Filter with Frequency DC to 3.87 GHz, Stopband Frequency 4.32 GHz, Insertion Loss 2.5 dB, Upper Rejection 30 dB @ 4.32 GHz, VSWR 1.70:1. Tags: Module with Connector. More details for QLF-3870-30 can be seen below.