The AGLPF040 from AmpliTech, Inc. is a Low Pass RF Filter with Frequency DC to 4 GHz, 3 dB Cutoff Frequency 4 GHz, Insertion Loss 2.50 dB, Upper Rejection 20 to 40 dB @5 to 5.5 GHz, Power 0.1 W. Tags: Die. More details for AGLPF040 can be seen below.