The CER0644A from CTS Electronic Components is a RF Duplexer with Frequency 1.75 to 1.85 GHz, Band 1 1.84 to 1.85 GHz, Band 2 1.75 to 1.76 GHz, Power 3 W, Insertion Loss 2.5 dB. Tags: Ceramic, Surface Mount. More details for CER0644A can be seen below.