"902SO" here refers to this mobile phone "Xperia 8".
This mobile phone 902SO meets Japanese technical regulations* and international guidelines for exposure to radio waves.
The Japanese technical regulations for exposure to radio frequency energy established permitted levels of radio frequency energy, based on standards developed by independent scientific organizations through periodic and thorough evaluation of scientific studies.
The regulations employ a unit of measurement known as the Specific Absorption Rate, or SAR.
The SAR limit is 2 watts/kilogram (W/kg) averaged over ten grams of tissue.
The limit includes a substantial safety margin designed to assure the safety of all persons, regardless of age and health.
The value of the limit is equal to the value given in international guidelines recommended by ICNIRP**, which is in collaboration with the World Health Organization (WHO).
The highest SAR value for this mobile phone is 0.89 W/kg*** when tested for use at the ear, and 0.50 W/kg*** when worn on the body in the below manner****.
While there may be differences between the SAR levels of various phones and at various positions, all phones meet the Japanese technical regulations.
Although the SAR is determined at the highest certified power level, the actual SAR of the phone during operation can be well below the maximum value.
* The technical regulations are provided in Article 14-2 of the Ministry Ordinance Regulating Radio Equipment.
** International Commission on Non-Ionizing Radiation Protection
*** The value is under simultaneous transmission use conditions.
**** Use at positions other than at the ear
This mobile phone may be used at positions other than at the ear. By using an accessory such as a belt clip holster that maintains a 1.5 cm separation with no metal (parts) between it and the body and the mobile phone, this mobile phone will comply with international guidelines for radio wave protection.
The World Health Organization has announced that "A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use." They note that if you want to reduce your exposure then you can do so by limiting the length of calls or using a hands-free device to keep the mobile phone away from the head and body.
For more information about SAR, see the following websites:
・Ministry of Internal Affairs and Communications (MIC)
https://www.tele.soumu.go.jp/e/sys/ele/body/index.htm
・Association of Radio Industries and Businesses (ARIB)
https://www.arib-emf.org/01denpa/denpa02-02.html (Japanese)
・World Health Organization
https://www.who.int/emf
Your mobile device is a radio transmitter and receiver. It is designed not to exceed the limits for exposure to radio waves recommended by international guidelines. These guidelines were developed by the independent scientific organization ICNIRP and include safety margins designed to assure the protection of all persons, regardless of age and health. The guidelines use a unit of measurement known as the Specific Absorption Rate, or SAR. The SAR limit for mobile devices is 2.0 W/kg and the highest SAR value for this device when tested at the ear is 0.37 W/kg*. As mobile devices offer a range of functions, they can be used in other positions, such as on the body. In this case, the highest tested SAR value is 0.56 W/kg* at the separation distance of 0.5 cm from the body. For electronic safety, maintain the separation distance with accessories containing no metal, that position handset a minimum of the above distance. Use of other accessories may not ensure compliance with RF exposure guidelines.
* The tests are carried out in accordance with international guidelines for testing.
Your handset is a radio transmitter and receiver. It is designed and manufactured not to exceed the emission limits for exposure to radio frequency (RF) energy set by the Federal Communications Commission of the U.S. Government.
The guidelines are based on standards that were developed by independent scientific organization through periodic and thorough evaluation of scientific studies. The standards include a substantial safety margin designed to assure the safety of all persons, regardless of age and health.
The exposure standard for wireless handsets employs a unit of measurement known as the Specific Absorption Rate, or SAR.
The SAR limit set by the FCC is 1.6 W/kg. The tests are performed in positions and locations (e.g. at the ear and worn on the body) as required by the FCC for each model.
The highest SAR value as reported to the authorities for this phone model when tested for use by the ear is 0.65 W/kg, when worn on the body is 0.20 W/kg and when WiFi hotspot mode is 0.46 W/kg. For body-worn operation, this phone has been tested and meets the FCC RF exposure guidelines. Please use an accessory designated for this product or an accessory which contains no metal and which positions the handset a minimum of 15 mm from the body. For devices which include "WiFi hotspot" functionality, SAR measurements for the device operating in WiFi hotspot mode were taken using a separation distance of 10 mm.
The use of accessories that do not satisfy these requirements may not comply with FCC RF exposure requirements, and should be avoided. The FCC has granted an Equipment Authorization for this model handset with all reported SAR levels evaluated as in compliance with the FCC RF emission guidelines. SAR information on this model handset is on file with the FCC and can be found under the Display Grant section of https://www.fcc.gov/oet/ea/ after searching on FCC ID PY7-11643I.
Additional information on Specific Absorption Rates (SAR) can be found on the FCC website at https://www.fcc.gov/general/radio-frequency-safety-0.