Power supply for USA

[gazum]

The connector is a positive-center 2.5mm barrel plug.

Is 2.5mm internal diameter or external diameter?

Will this power adapter work for the USA? It is described in the specs as

DC cable with 2.5 mm x 5.5mm barrel plug.

Has anybody bought a similar adapter from amazon or ebay?

Thank you.

[olimex]

external diameter is 5.5 mm
internal diameter is 2.5 mm

[Lurch]

Just make sure the device you want to really uses 2.5mm.
Olimex, for example, almost always uses 2.1mm
Some companies off power supplies with interchangeable tips so you can adapt.