The CER0023B from CTS Electronic Components is a RF Duplexer with Frequency 1.85 to 1.99 GHz, Band 1 1.93 to 1.99 GHz, Band 2 1.85 to 1.91 GHz, Operating temperature -20 to 70 Degree C. Tags: Ceramic, Surface Mount. More details for CER0023B can be seen below.