The R04-M1775-02 from SRTechnology Corporate is a RF Duplexer with Frequency 1.77 to 1.869 GHz, Band 1 1.77 to 1.78 GHz, Band 2 1.86 to 1.869 GHz, Insertion Loss 0.8 to 1.5 dB, Isolation 80 to 100 dB. Tags: Module with Connectors. More details for R04-M1775-02 can be seen below.