The FMSP1039 from Fairview Microwave is a RF Surge Protector with Frequency DC to 3 GHz, Input Power 40 W, Insertion Loss 0.1 to 0.25 dB, Operating Temperature -55 to 85 Degree C, Return Loss 26 dB. Tags: Gas Discharge Tube. More details for FMSP1039 can be seen below.