The 28-37-02G from TX RX Systems is a RF Duplexer with Frequency 144 to 174 MHz, Band 1 144 to 174 MHz, Power 400 W, Insertion Loss 1.5 dB, Isolation 50 dB (Between Channel) / 85 dB (Per Channel). Tags: Rack Mount. More details for 28-37-02G can be seen below.