Haase and Martin says the tab bar icon collection (http://www.iconsberlin.com/) made by iconsBerlin was revised recently and 51 icons were added.

In the section, navigation, different Icons were added — which, for instance, symbolize functions like the changing of settings or updating process. The whole collection includes 578 tab bar icons and is available worldwide.

All icons support the high resolution of the iPhone 4 retina display. So each tab bar icon appears in a size of 60 x 60 pixels. In addition app developers get all icons in a smaller size that is 30 x 30 pixels which are used on iPhone 3 apps and on the iPad. Icons Berlin costs approximately US$72.