A 2-in-1-out coupler is a microwave device used to combine two input signals into one output signal. This type of coupler is commonly used in wireless communications systems, radar systems, and other microwave frequency applications. It can couple two input signals to one output port, or from one input signal port to two output ports, depending on its design and use. This type of coupler usually has low insertion loss, high isolation and wide-band characteristics, which can effectively couple and distribute signals and is suitable for various microwave communication and radar system applications.