Which routers can work in 110/220V environment?

I'd like to buy a router here in North America (110V/60Hz) and send it
to somebody in India. They use the European 220V/50Hz system down
there. Most laptops I've seen have transformers that are capable of
handling this multi-format electricity, but I don't know if any routers
come with this kind of transformer. I'm mostly used to D-link routers,
so I've looked at the transformers on it, and they're only capable
working in a 110V environment. Do any of the Netgears, Linksys have
this capability?

Basically I'd like to not have to buy a separate transformer that'll
convert from 220V to 110V. Ideally the only thing I'd need to buy would
be a simple North American/European prong-converter, and nothing more.

Yousuf Khan