The DDTO-1-40-K from Shanghai Huaxiang Computer Communication Engineering is a Dual Directional Coupler with Coupling 40 dB, Coupling Variation 0.8 dB, Frequency 500 MHz to 1 GHz, Average Power 400 W, Insertion Loss 0.3 dB. Tags: Module with Connectors. More details for DDTO-1-40-K can be seen below.