iPhone SDK - what is this control? Is it custom?

What is this control? Or is it something that has been custom made? I see it in the Twitter and several other applications. I'm referring to the two 开发者_运维百科triangles, and if you've ever used them, they refresh the view below them, usually going through a list of content items.

(I'm not referring to the navigation controller with a back button)

They are UISegmentedControls with custom images and the style set to UISegmentedControlStyleBar.

Its right there in Apple's NavBar sample code. You have the entire source code for the project. Search for NavBar within the Documentation and API reference item under the Help menu of Xcode 4.