1 Incorporate our alphabet set of iOS icons into your concepts, designs and builds.
All icons are provided as PNGs, white on flat colours. You can use Photoshop’s Hue/Saturation adjustment layer to customise the colours for yor project.
2 Simply, download,open and use in your designs.
The PNGs are provided in sizes suitable for every iOS device,allowing you to create mock-ups and designs for both iPhone and iPad app.
These icons are:
Free for commercial use
Both square and rounded corners versions are included.
Saved as PNGs with transparency
This freebie designed and released by Make it Digital 
Size:1.43 MB

Licence: according to author of this freebie, you can use them anywhere you like!
Like this freebie? You can download icons from here