has released Featherweight UI – A free, vector based and retina ready UI kit for web designers. Every element is vector based, retina ready and distributed through layers. Text and colours are easily editable. This kit is completely free for use for personal or commercial projects.
The font used is Lato Normal, available from Google Web Fonts for online or offline use.
Using vector shapes in Photoshop is optimal especially for UI based elements, as you can easily scale objects targeting various resolutions. Leveraging Illustrator for complex shapes, you can use your custom shape definitions for styling in Photoshop with simplified cross-product workflows.
Download Featherweight UI kit for web designers from here