Mozilla Firefox for iOS (Firefox for iOS — Mobile Web browser for your iPhone, iPad and iPod touch)
Source: You can now browse the web with Firefox on your iPhone and iPadAs for features, Firefox for iOS brings to the table private browsing, intelligent search, account sync, visual tabs and quick access to top-visited websites. If you're a fan of the desktop browser and actively utilize Mozilla's cloud sync you'll definitely want to check out this mobile app to really take the experience to the next level.
It's worth noting that iOS 9 or above is required for private browsing.