This package contains 7 skybox materials for dawn, day, fog, sunset and night. Each material is made from 6 skycube textures (6 x 2k squared).
You can buy this package at:
https://www.assetstore.unity3d.com/en/#!/content/91122
Sky Cube Materials Set
GESO Media 
Hello.
Is this material set use on mobile device?
Gefällt mirGefällt mir
Yes, it can be used on any target platform.
Gefällt mirGefällt mir