The CER0691C 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 20 to 200 W, Insertion Loss 2.3 dB. Tags: Ceramic, Surface Mount. More details for CER0691C can be seen below.