On many country's we don't use the same Volt. That's why the same brand can have both, here in Canada we use 120 and mostly in Europe is 240.
If I want to use European router in my country, I need a converter.
The 220 volt routers are more powerful. On 120 volts,15 amps, less than 2.5 horsepower is all that is possible, despite what manufacturers say (they lie). On 220 volts, 15 amps, 4 horsepower is possible. So, when Europeans rate a router at 3.25 horsepower, they mean it. When Americans rate a router at 3.25 horsepower, they lie.