My wife got the blue X4, so she wanted a clear case to still see the color, so I got this one:

https://smile.amazon.com/gp/product/B074RH71XD/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1

Actually looks great on the phone, feels nice, and is actually very slim overall. Very happy with it.

I ordered this one for my wifes x4. Should be here today or tomorrow.

https://www.amazon.com/gp/product/B074RH71XD/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1