The CHPFL-0300 from Crystek Corporation is a RF High Pass Filter with Frequency DC to 300 MHz, Insertion Loss 3.34 to 101.36 dB, Power 4 W, Return Loss 0.01 to 4.61 dB, Operating_Temperature -40 to 85 Degree C. Tags: Connectorized, Butterworth. More details for CHPFL-0300 can be seen below.