The L2509 from Mercury Systems is a Band Stop Filter with Stopband Frequency 1626.5 to 1660 MHz, Insertion Loss 5 dB, Rejection 45 dB from 1626.5 to 1660 MHz, Upper Rejection 45 dB, Power 0.01 W. Tags: Module with Connectors, Cavity Filter. More details for L2509 can be seen below.