Currently, you can pre-order and pay full fare for an iPhone 6S through one of the major carriers at the Apple site but can't pre-order and pay full fare for an iPhone 6s from the Apple Store -- I guess what was called a "SIM free" phone. Verizon sells its iPhones unlocked, but even with the GSM and CDMA technology, I'm told (by Verizon) that just putting in a SIM from another carrier in the US or overseas won't give you LTE speeds. The phone will work, they say, but LTE is an issue ... according to Verizon. Now, after three calls to Apple, no one can tell me the why and what of Apple's SIM free model (or whatever it's called model) is all about. They had this for the iPhone 6 and will likely have it for the 6s in weeks or months. What does this model purchased directly from Apple do that an iPhone bought through a major carrier doesn't? Does it have a different chip, for example, that works well with LTE no matter what network you hook into once the SIM card is inserted? How come no one at Apple can explain what seems to me a straightforward question. Do I have to contact one of their "geniuses?"