Inline 2-port Junction
The EW-JC200 2-port inline junction allows you to connect two EW-SD50 electric wires to each other. The most likely scenario where you'd need to do this is when using the EW-JC130 Y-connector and a bar-end junction box.
Note that the JC200 and the EW-WU111 are about the same size, but the latter also adds wireless communications to the system. If you need a 2-port junction it may be worth it getting the Wireless Unit instead.