Samsung Galaxy S III (CDMA)
Replying to: Why no SIM card Sprint? by mbrenner
Most chipsets in most phones have some level of "support" for a hundred or more features that may not be implemented in that particular phone. There are also radio chips and antennas that need to be added; all kinds of extra parts and engineering that go into it.
It's not at all like Sprint could flip a switch or add one part to enable GSM. They didn't "cripple" or disable anything. There's much more involved. The Verizon version with GSM is a different, more complicated phone.
Shop for accessories specifically compatible with the Samsung Galaxy S III (CDMA).