How do dual-sim adapters work?

[Indigo]

To start with I've received my Nokia Lumia 620 in the post today and awaiting my Ovivo sim card to put in it tomorrow or Thursday hopefully.

Was thinking of getting a second sim card from Ovivo purely for data but wondering if it's possible to have two sim cards in the phone at the same time? Or does it need changing each time I want to use a different sim?

 

[Indigo]

I don't make a lot of calls to be honest so don't mind having to switch sim cards often as long as it's an option to at least keep them both in the phone.

What kind of adapter would I be looking at then? Are they pretty generic or would I need one specific to my phone?

 

[Indigo]

It does indeed use a tray loader. No problem if it doesn't work as not a major issue. Just slightly easier.

Cheers for the help.