Lumia 640 Case (Sky Blue) by CoverON [Slender Fit] Series Hard Protective Slim Back Phone Cover For Microsoft Lumia 640 Case Introducing the [Slender Fit] phone case series for the Microsoft Lumia 640! Made of rigid polycarbonate plastic (that's a fancy way to say it's very durable and protective) No bulk to be found here, the case is formed from 1-piece for an incredibly slim fit Features a rubberized coating for a great feel and a slip-free grip Stress free 90 day manufacturer warranty