From the FCC website: "The FCC ID number is usually shown somewhere on the case of the phone or device. In many cases, you will have to remove the battery pack to find the number. Once you have the number proceed as follows. Go to the following Web address: www.fcc.gov/oet/ea/fccid. Once you are there... Enter the FCC ID number (in two parts as indicated: 'Grantee Code' is comprised of the first three characters, the 'Equipment Product Code' is the remainder of the FCC ID). Then click on 'Start Search.' The grant of equipment authorization for this particular ID number should appear. The highest SAR values reported in the equipment certification test data are usually included in the comments section of the grant of equipment certification."
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).