Voice quality is not tested here (that comes later), but Sprint uses a dummy head to simulate real-world use. The head's shell is plastic, but inside it's filled with gel to resemble the density of a human brain. The phone is then positioned a set distance to one side. Though Sprint has unique criteria for its tests, handset manufacturers and other carriers use a similar process when evaluating devices. You'd even find such an arrangement at the Federal Communication Commission's labs in Columbia, Md., where the agency tests the Specific Absorption rate (SAR) of handsets sold in the United States.