What is the difference between a modular and a monoblock UPS

Monoblock are fixed capacity uninterruptible power systems. To scale or add N+X resilience, another monoblock UPS must be installed i.e. 2 × 100kVA to give 100kV N+1 or 200kVA capacity. With a modular UPS, an additional UPS module can be added to a UPS frame to provide N+1 redundancy or increase the power capacity up to the maximum number of UPS modules that can be housed by the frame. The modular UPS system can be expanded further by adding another UPS frame.