A standard US 3 pin (120V) plug will fit that "universal" outlet so you could make an adaptor easily (do stick labels on it).
These inverters generally produce a floating output (no N-E bond) so, if the 230V appliance doesn't need a neutral and doesn't mind 50Hz then you're good to go.
If you need 115-0-115 for your appliance, you'll need an autotransformer.