The BWLF-4R5 from Sainty-Tech Communications Limited is a Low Pass RF Filter with Frequency DC to 4.5 GHz, 3 dB Cutoff Frequency 4.5 GHz, Insertion Loss 1.7 dB @4.5GHz, Rejection 20 dB @7.5GHz, 40 dB @9.7GHz, Power 30 dBm. Tags: Die. More details for BWLF-4R5 can be seen below.