The 28-37-07C 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 0.7 dB, Isolation 30 dB (Between Channel) / 85 dB (Per Channel). Tags: Rack Mount. More details for 28-37-07C can be seen below.