Coveroo Oklahoma State University - Big O design on a Black-Black iPhone 4/4S Guardian Case Ride on Cowboys! Show your support for Oklahoma State University with this official Coveroo! This protective snap-on case for the AT&T, Verizon and Sprint iPhone 4/4S is an authentic iPhone accessory made by Coveroo, customized with a design of your choice. The design is printed using our HighColor process. Not a sticker or skin. Handmade by our team in San Francisco, CA