SWPS used at 110v instead of 230v Question??

I have 4 mobile phones and chargers, all different manufacturers.
(Sony, Siemens, Nokia, Motorola)

All apart from one (Sony Ericcsson) have labels stating 230v use only,
one states 110v-240v.

All seem to be made by Astec of China

All 4 give an indication on the phone that enough voltage is being
supplied to charge the phone when used at 110v, plugged into my bathroom
110v shaver socket.

Is it just a label thing, in fact are all these chargers capable of
being used on 110v, in America, without the need to buy a specific 110v
travel charger ?

As I understand it, they may be switched mode power supplies, the
technology I know very little about.

Does it do any harm to operate these chargers on 110v, instead of the
labelled 230v ?

How do I tell if it's switched mode from the outside, or if I open it up
?
Thanks

 

SWPS used at 110v instead of 230v Question??


OOPS

Should read

SMPS used at 110v instead of 230v Question??

Reposted with correct header, ignore this one !!