The CER0645A from CTS Electronic Components is a RF Duplexer with Frequency 1.53 to 1.66 GHz, Band 1 1.53 to 1.56 GHz, Band 2 1.63 to 1.66 GHz, Power 3 W, Insertion Loss 2 to 2.2 dB. Tags: Ceramic, Surface Mount. More details for CER0645A can be seen below.