One way a UPS system can help ensure continuous availability is to include redundant (or "extra") components within its chassis, known as "N+1" redundancy. Tripp Lite "N+1" Single-Phase UPS systems (available in 12, 16 and 20 capacities) feature two UPS power modules for internal "N+1" redundancy. If one power module is removed for maintenance, the other power module will support the equipment load (as long as it does not exceed the capacity of the power module). Like other modules, Tripp Lite N+1 Single-Phase UPS systems also include a hot-swappable power distribution module to ensure continuous availability if both power modules need to be removed for maintenance.