You could make whatever size you want - in this case - the larger circle is 4" (in the blue) and the smaller one is 3".
The black is about 1/4 inch wider...just to pop the colour.
The background is made using the 'shaving cream' technique...(smells so good). Although I have created my own to suit my colour scheme, Imagine Design Create have their own range of designer paper including the Marbled Sea and Sky paper pack.
I have a couple of friends battling Cancer and thought this would be an ideal card to send. Such a fight !!