The CER0290B from CTS Electronic Components is a RF Duplexer with Frequency 3.43 to 3.55 GHz, Band 1 3.53 to 3.55 GHz, Band 2 3.43 to 3.45 GHz, Power 2 to 20 W, Insertion Loss 3 dB. Tags: Ceramic, Surface Mount. More details for CER0290B can be seen below.