Main unit: JB-2MD Expansion main unit: JB-2HD Sub unit: JB-DA Total of 4 sets. I tested with temporary wiring as shown in photo 2. While sufficient for voice calls and conversation, the sound quality is not quite right, possibly due to aging. Image monitoring was possible, but the images from the expansion main unit (JB-2HD) were dark on both sub-unit screens (photos 9, 10). One of the sub-unit camera covers is yellowed and has debris inside, which I was unable to disassemble and remove. (Photo 6) The cover frame of the sub-unit has a crack. (Photo 15) Please understand that all 4 units have some discoloration and dirt. The JB-2HD (photo 13) has a 100v cable cover that the JB-2MD does not have (photo 14, arrow). Power cables and connection cables are not included. There are no manuals either.