Small red round delete buttons

How can I create one of these small red ro开发者_运维知识库und delete buttons like in the safari app (at the top and left of a tab)? Is it a default UIButton with an image or an pre-defined button of the iOS SDK?

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I got it somewhere http://img37.imageshack.us/img37/6804/buttoniry.png

I think there is no such pre-defined button of the iOS SDK