does not work for transferring files, mostly good for USB charging
I bought this for a Macbook pro and have tried several devices ranging from iOS devices to Samsung Galaxy S7 to a Sandisk USB reader. For the most part it just works for charging. It doesn't reliably recognize iOS for sync and iTunes and will not recognize Samsung Android devices or other USB card readers at all for sync and transferring files. It's overpriced considering it's basically a fancy USB charger and that's it.