The AD1857-1937D284 from Anatech Electronics is a RF Duplexer with Frequency 1850 to 1865 MHz / 1930 to 1945 MHz, Band 1 1850 to 1865 MHz, Band 2 1930 to 1945 MHz, Insertion Loss 1 dB, Isolation 70 dB. Tags: Module with Connectors. More details for AD1857-1937D284 can be seen below.