The X3906 from Mercury Systems is a Low Pass RF Filter with Frequency 1 to 8000 MHz, Stopband Frequency 9500 to 10500 MHz / 10501 to 20000 MHz, Insertion Loss 1 dB, Rejection 50 to 65 dB, Upper Rejection 50 to 65 dB @9500 to 20000 MHz. Tags: Module with Connector. More details for X3906 can be seen below.