The 851-871-MF4 from Broadwave Technologies is a Impedance Matching Pad with Frequency DC to 4 GHz, Input Power 1 W, Attenuation 5.7 dB, Operating Temperature -55 to 100 Degree C, VSWR 1.45:1. Tags: Connectorized, 50 to 75 Ohms. More details for 851-871-MF4 can be seen below.