The R04-M1775-01 from SRTechnology Corporate is a RF Duplexer with Frequency 1.77 to 1.869 GHz, Band 1 1.77 to 1.779 GHz, Band 2 1.861 to 1.869 GHz, Insertion Loss 1.4 to 1.5 dB, Isolation 100 dB @ 1770 to 1869.5 MHz. Tags: Module with Connectors. More details for R04-M1775-01 can be seen below.