level of site visitor not logged in

Following from a previous post I thought it might be best to start a new thread, so that another related question could be answered.

Using s2member conditionals could someone provide me with the user level for a user who is not logged on as I want to display one message to non logged in site visitors and another to registered logged in members

[s2If current_user_is(s2member_level?????)] <– What would this level or statement be?
Content shown to non logged in site visitors
[/s2If]
[s2If current_user_is(s2member_level0)]
Content exclusively for members level 0.
[/s2If]

Thanks

I added a reply to your other post Jon. :)