The DO-18dB-400 from Wuhan Zhongyuan Tiankui Technology Development is a Directional Coupler with Frequency 350 to 480 MHz, Coupling 18 dB, Insertion Loss 0.3 dB, Isolation 20 dB, PIM -120 dBc. Tags: Module with Connectors. More details for DO-18dB-400 can be seen below.