If you take good a look at the DROID ULTRA, you'll notice that there is no visible slot to insert the SIM cad. Instead, Motorola is using the Volume rocker as a removable button/SIM card tray. Not only does this unique feature saves space, it also helps to keep the exterior design clean.
To access your SIM, all you need to do is slide a fingernail under the bottom of the Volume rocker and simply pry the entire tray out. To put it back, make sure the “UP” side is up and press until it clicks. Clever thinking Motorola!
Source: droid-life.comAdded: 8 October 2013