The QLF-3500-40 from Qualwave is a Low Pass RF Filter with Frequency DC to 3.5 GHz, Stopband Frequency 3.8 to 5.18 GHz, Insertion Loss 1.5 dB, Upper Rejection 40 dB @ 3.8 to 518 GHz, VSWR 1.50:1. Tags: Module with Connector. More details for QLF-3500-40 can be seen below.