The OnePlus X is probably the first time that OnePlus has really deviated from their design language. Yes, the OnePlus 2 was different from the OnePlus One in a few obvious ways but the basic shape, ergonomics etc remained quite similar. While it did feel like an improvement, people could still probably tell that it was a OnePlus device especially when they touched the sandstone back. The OnePlus X on the other hand feels totally new. The design of the OnePlus X has both glass at the front as well as the back on the Onyx version and a Ceramic back on the Ceramic version.