Apple iPhone 4 - Manual (Page 7)

Exposure to RF energy is related to time and distance. If you are
concerned about RF exposure, decrease your total talk time on iPhone
and increase your distance to iPhone by using one of the many
hands-free options available, including the built-in speakerphone, the
supplied headphones with built-in mic, or other third-party accessories.
For more information about RF energy exposure, see the FCC’s Radio
Frequency Safety page at: www.fcc.gov/oet/rfsafety
For information about the scientific research related to RF energy
exposure, see the World Health Organization’s EMF Research Database at:
www.who.int/peh-emf/research/database
GSM Model
Frequency Band 2 Body 3 Head FCC & IC 1g SAR Limit (W/kg)
GSM 850 1.11 1.00 1.6
GSM 1900 0.43 1.17 1.6
UMTS II 1900 0.43 1.17 1.6
UMTS V 850 1.11 1.00 1.6
2.4 GHz Wi-Fi 0.07 0.88 1.6
Frequency Band 2 Body 3 Head EU 10g SAR Limit (W/kg)
EGSM 900 0.74 0.66 2.0
GSM 1800 0.28 0.59 2.0
UMTS I 2100 0.36 0.93 2.0
UMTS VIII 900 0.74 0.66 2.0
2.4 GHz Wi-Fi 0.05 0.36 2.0
CDMA Model
Frequency Band 2 Body 3 Head FCC 1g SAR Limit (W/kg)
800 MHz Band Class 0 0.87 1.06 1.6
1900 MHz Band Class 1 0.45 1.18 1.6
2.4 GHz Wi-Fi 0.15 0.54 1.6
2 Your iPhone may be configured to support one or more of the listed
frequency bands, depending on carrier technology and network
availability. The frequency band used by iPhone varies depending on
wireless service provider, wireless technology, and region.
3 iPhone positioned 10 mm (13/32 inch) away from the body.