SHORT VERSION:----------------------------You may not be able to know for sure if you will get the XT1103 (model 00630NARTL) or the XT1100 (model SM4034AW4N3) when you purchase this phone on Amazon. I bought one for myself (sold directly from Amazon) and then bought one for my wife about a month later (sold from DeltaMobiles via Amazon). I got the XT1103 US model on the first order (from Amazon), then got the XT1100 international/euro model on the second order (from DeltaMobiles). This is a problem because the XT1100 cannot use 3G or LTE on my carrier (Consumer Cellular, which piggybacks on the AT&T network) or on virtually any other US cellular carrier. So even though I went back into my Amazon order history and purchased the second Nexus 6 using the same product page as the first that I bought, the second was a different model that will not be able to utilize high-speed data. See the photo attached to this review which shows both boxes side-by-side. I am returning the XT1100 and I bought my wife another Nexus 6 directly from the Google Store to be sure I will get an XT1103 that is set up for US data networks (it was the same price as Amazon when I bought it just now). I use Amazon all the time for all kinds of things, but in this case I would recommend that you avoid purchasing a Nexus 6 through Amazon unless it is clear exactly which model you're going to receive. You are SUPPOSED to get an XT1103 when you buy the phone on this product page - note that in the Technical Details section on the product page it specifically has "00630NARTL" as the item model number, which is the US-compatible XT1103, so if you get an XT1100 (model SM4034AW4N3) you are getting the wrong phone. I am suspicious that DeltaMobiles is purposely sending people the wrong phone.LONG VERSION:----------------------------I love this phone. This is my first Android phone after three iPhones and I couldn't be happier. I love the huge, bright screen, the camera is pretty nice, the phone is fast, and LTE is awesome.But here's why I wrote this review: I purchased my Nexus 6 on May 7th, 2015. It shipped from Amazon (in other words it says "Ships from and sold by Amazon.com" under the price on the Amazon product page), and I got the XT1103, which is the US model. It only took a few minutes to set it up on my service (Consumer Cellular, which piggybacks on the AT&T network), and it hooked up to LTE immediately. You probably already know this if you are shopping for a high-end smartphone, but LTE (aka 4G LTE) is the most recent high-speed data network. It means faster downloading, web browsing, etc. and is one of the major benefits of upgrading to a new phone if your current phone is not LTE-capable.My wife was jealous of my new, giant, beautiful phone, which is understandable since I intentionally showed it off to her all the time and often suggested the inferiority of her old iPhone (which was a hand-me-down from when I made my previous iPhone upgrade). So for our anniversary, I bought her a Nexus 6 as well (purchased on June 16th, 2015 - a little over a month from when I bought mine). I gave it to her today, and then started setting it up for her. Everything in the setup went normally just like it had with my phone, but when I disabled the wi-fi to test the data network, I noticed that her phone was not connecting to LTE (or 3G for that matter). I set both our phones side by side and checked the APN settings and some other phone settings to verify that they were set up identically, which they were. I had only taken the phone itself out of the box up to this point, and when I removed the rest of the contents I saw the European plug on the phone's charger. I compared the box of her phone to mine (see attached photo) and finally realized by looking at the labels that my wife's Nexus 6 was the XT1100 (euro/international model), and that I had gotten the XT1103 (the US version). While the XT1100 looks identical, has an identical OS, uses the same nano sim card, etc., it has a very different setup in terms of compatible cellular networks and will not use US 3G or LTE. Note that the XT1100 will still work for making calls and using basic cellular data (GSM), but you will not be able to access 3G or LTE.I was pretty certain that I had bought my wife's Nexus 6 from the exact same product page on Amazon from which I had purchased my own, so I went back into my order history to verify this. Both of the orders do point to the same product page, but the first order (XT1103 US model) was sold by Amazon, while the second order (XT1100 international model) was shipped/sold by DeltaMobiles. Currently (June 20th), the product page says it is being sold/shipped by Amazon again. I didn't even realize that it was a different seller when I made the second purchase.This situation is pretty frustrating because nobody buying this phone to use it in the US would likely choose the international model instead of the US model since the international model will not perform as well on US networks, so I don't know why they are sending the XT1100 to US customers. Because the seller (DeltaMobiles) covered the SM4034AW4N3 model number on the box with a separate tag (see the photo attached to this review) I became a little suspicious that they are intentionally sending people the wrong phone because many people may not know that the XM1100 is the wrong phone. After all, it is a genuine Nexus 6, it will place phone calls in the US, and it will be able to use cellular data, so many people may start using it and never realize (or only realize too late) that they've gotten the wrong phone that can't use the much faster 3G and 4G data networks. If it is possible for a seller to make a little more money by sending the XT1100 to customers in the US than by sending them the correct XM1103, I bet this would explain why DeltaMobiles is sending out the wrong phone.For your reference, these are the compatible networks for the two versions of the phone:XT1103 (Model 00630NARTL) :GSM: 850/900/1800/1900 MHzCDMA band class: 0/1/10WCDMA bands: 1/2/4/5/8LTE bands: 2/3/4/5/7/12/13/17/25/26/29/41CA DL bands: B2-B13, B2-B17, B2-29, B4-B5, B4-B13, B4-B17, B4-B29XT1100 (Model SM4034AW4N3)GSM: 850/900/1800/1900 MHzWCDMA bands: 1/2/4/5/6/8/9/19LTE bands: 1/3/5/7/8/9/19/20/28/41CA DL bands: B3-B5, B3-B8And if you put the search term "List of LTE networks" into Google, you can go to a Wikipedia page that will show you all of the individual networks and what bands they use for LTE.