Different countries produce and utilize power in different ways. APC manufactures UPS systems and surge products specific to those different environments. For example, North America has input voltage levels of 120 volts at 60Hz. Most European countries utilize an input voltage of 230 volts at 50Hz.
APC's North American units have an input requirement of 120 volts, 50-60Hz and an output of 120 volts, 50-60Hz. APC's international models have an input requirement of 230 volts, 50-60Hz and an output of 230 volts 50-60Hz. APC does not recommend the use of domestic models overseas due to the potential risk of damage to either the ups or the load, even with a transformer.
If you have questions pertaining to what model you should use in a specific country please refer to the product section of APC's web site. Here you will be able to view input and output voltage levels, corresponding model numbers, and recommended countries for usage.
http://www.apc.com/products/