Sorry for the slow reply. I put two vertical stips on the back of my devices where my fingers rest. Or like on my surface pro horizontally but closer to the edg

Sorry for the slow reply. I put two vertical stips on the back of my devices where my fingers rest. Or like on my surface pro horizontally but closer to the edge just to catch my fingers if it starts slipping out my hand. I think the most curved device I have it on is my kindle. These are pliable enough that they should fit some pretty serious curves.