Asus Zenfone 4 flip covers are available in four colors (Maroon, Black, White, Pink).
Below I have mentioned flip-covers with their price and their availability on online stores.
Coverage Flip Cover For Asus Zenfone 4
DMG S View Flip Book Cover Case for Asus Zenfone 4
Koloredge Flip Cover For Asus Zenfone 4 A 450 Cg Black
Nillkin Sparkle Leather Flip Case For Asus Zenfone 4 A450cg- White
Acm Leather Diary Folio Flip Flap Case For Asus Zenfone 4 4.5 Inch A450cg -black