The F3751 from Teledyne Microwave Solutions is a Band Stop Filter with Stopband Frequency 0.25 to 1.5 GHz, Bandwidth 4 to 110 MHz, Insertion Loss 1.5 dB, Power 0.001 W, Return Loss 10 dB. Tags: Module with Connectors, Notch Filter. More details for F3751 can be seen below.