This is the Carrozzeria FM antenna distributor RD-FD20. It's a device that splits a vehicle's radio antenna into FM/AM for audio and FM-VICS for FM multiplex broadcasting. It also has a built-in booster to compensate for the loss from the split. It's primarily for Carrozzeria navigation systems, but it can be used universally by connecting ACC and GND. All included accessories are shown in the photos. The input/output antenna terminals are as follows: Radio antenna input: JASO Radio antenna output: JASO FM multiplex antenna output: JASO