Particles for applications UI. Contains full vector Photoshop layers merged into good named layer groups. Threre’re both two versions: for regular desktop apps and for Retina/HDPI apps. Knobs, sliders, switches, bars on light gray background. Also contains some useful things like embossed borders and hidden bonus. Good for audio software and sound widgets.
Font used: Gotham Pro (but you can use ANY sans-serif font you want!)
http://www.typography.com/fonts/font_styles.php?productLineID=100008