Arduino Relay Controll

I want to control a relay with an arduino uno. The relay I'm going to use is this one I plan on using it to control 12 volt fans is it 250 volt ac or dc. because if its ac I can wire up an edison outlet and plug in the transformer to it. Are there any other parts I need. Will 12 volts be ok on the 250 volt output side.

That is all you need, the relay is driven by the 5V coming from the arduino, and is using a 2N2222 to pull the relay.

The voltage on the contact side in the relay does not matter, as this is a mechanical relay. Just stay under the values printed on it.