The Mitsubishi PAC-MKA31BC branch box is a refrigerant manifold and is used to ensure optimal refrigerant flow to the connected indoor units, as well as provide a less bulky finish to the outdoor unit. The PAC-MKA31BC has ports for connections to 3 indoor units and can be connected directly to the condensing unit, or branched with a MSDD-50AR-E or MSDD-50BR-E to a secondary branch box to add support for up to 8 zones.