Most monoblock UPS can be operated in a parallel N+X operation to provide redundancy and additional resilience. Each UPS in the parallel configuration will require a parallel operation card for output and system synchronisation. In a parallel UPS system, one UPS will operate as the Master unit and the rest as Slave systems. Parallel UPS installations can save energy through cycling roles. Costs can be saved using a centralised battery or each UPS can be installed with its own battery set.