The CSI-FLTR-PCSNF20 from Westell Technologies is a Band Stop Filter with Stopband Frequency 1.850 to 1.990 GHz, Insertion Loss 1.3 dB, Rejection 20 to 40 dB, Power 20 W, VSWR 1.35:1. Tags: Module with Connectors, Cavity Filter. More details for CSI-FLTR-PCSNF20 can be seen below.