The CER0541A from CTS Electronic Components is a RF Duplexer with Frequency 1.85 to 1.99 GHz, Band 1 1.85 to 1.91 GHz, Band 2 1.93 to 1.99 GHz, Power 6 W, Insertion Loss 3 dB. Tags: Ceramic, Surface Mount. More details for CER0541A can be seen below.