The CER0372A from CTS Electronic Components is a RF Duplexer with Frequency 3.5 to 3.65 GHz, Band 1 3.6 to 3.65 GHz, Band 2 3.5 to 3.55 GHz, Insertion Loss 3.4 dB, Operating temperature -30 to 80 Degree C. Tags: Ceramic, Surface Mount. More details for CER0372A can be seen below.