Do you remember the article we did about the dual sim Galaxy Note II ?
Well the website Unwired view found a website which listed the I939D and might be available only in China.
Only this is not a normal Dual Sim phone it doesn’t support two GSM SIM cards, but a GSM one, and a CDMA one (usable on China Telecom).
The Galaxy S III i939D is exact copy from the international S III (the black model, to be more precise). And it runs Android 4.1.1 Jelly Bean, and comes with usual Galaxy S III features which are a 4.8 inch sAMOLED HD display, Exynos 4412 1.4GHz quad-core processor, 1GB of RAM, 1.9MP front-facing camera, and an 8MP rear camera with LED Flash.