The AD1937-1972D278 from Anatech Electronics is a RF Duplexer with Frequency 1930 to 1945 MHz / 1965 to 1980 MHz, Band 1 1930 to 1945 MHz, Band 2 1965 to 1980 MHz, Insertion Loss 1 dB, Isolation 30 dB. Tags: Module with Connectors. More details for AD1937-1972D278 can be seen below.