android - Is getSimCountryIso returning 3 letters or 2 letters ISO code -

i wondering, getsimcountryiso returning 2 letters or 3 letters iso code? not being mentioned in documentation. tested nexus phone, returning 2 letters. however, i'm not sure true other phones.

it returns whatever oem has configured gsm.sim.operator.iso-country property, in experience 2-character code. codes have seen match alpha-2 code iso 3166-1 (http://en.wikipedia.org/wiki/iso_3166-1). based on observation unable find in official documentation.