The CER0397B from CTS Electronic Components is a RF Duplexer with Frequency 1.71 to 1.88 GHz, Band 1 1.81 to 1.88 GHz, Band 2 1.71 to 1.79 GHz, Power 3 W, Insertion Loss 3.6 to 3.8 dB. Tags: Ceramic, Surface Mount. More details for CER0397B can be seen below.