Allows connection of two indoor units (same type and capacity) to one outdoor unit Replacement technology (R22 & R407c). Twin-operation is possible with all light-commercial indoor units (except XT models) 95% of SDI systems are ‘A’ rated Infra-red and wired controls available The Super Digital Inverter Twin-Split system connects two indoor units of the same type and capacity to one outdoor unit in order to ensure more air distribution in a larger area/room. The units operate as a group sharing the same operating conditions to achieve set point against there own return air sensor. The units are suitable for use with either new R410A refrigerant pipework, or indeed can be used as ‘replacement technology’ enabling the re-use of existing R22 or R407c pipework.