The WHK4-45-50-40-1000-20 from Wainwright Instruments is a RF High Pass Filter with Frequency 45 / 50 MHz to 1 GHz, Insertion Loss 0.5 to 0.75 dB, Power 20 W, Rejection 40 dB, VSWR 1.50:1. Tags: Module with Connectors, Lumped Component Filter. More details for WHK4-45-50-40-1000-20 can be seen below.