SAR stands for Specific Absorption Rate is the unit of measurement for the amount of Radio Frequency energy absorbed by the human body when using a mobile phone. SAR value is expressed as a measure of the maximum energy absorbed by a unit of mass of exposed tissue of a person using a mobile phone, over a given time or more simply the power absorbed per unit mass.
SAR values are usually expressed in units of watts per kilogram (W/kg) in either 1g or 10g of tissue. Every country has a regulatory threshold value of SAR for mobile phone devices. In India the regulatory unit being 1.6 W/kg.