The PDLF-R37 from Sainty-Tech Communications Limited is a Low Pass RF Filter with Frequency DC to 0.37 GHz, 3 dB Cutoff Frequency 0.37 GHz, Insertion Loss 3.0 dB @0.37GHz, Rejection 25 dB @0.5GHz, 40 dB @0.55GHz, Power 30 dBm. Tags: Die. More details for PDLF-R37 can be seen below.