Dual SIM Adapter, Portable Battery Case for iPhone 7 ( IOS 7.0 or Above ), 2200 mAh Capacity, Ultra Slim, Black, Bluetooth( V4.0 or Above), by Wook

Works like a charm. The only issue I encounter is sometimes the signal seems bad. Not sure yet if this is the provider. The second sim card I'm currently using in this device is from a provider known to have many issues lately. I still need to be available (because of my clients) on this net.Other than the aforementioned, the device works nicely. Love it!

Directions were near impossible to follow. Hard to understand the right sequence of button-pushing to turn the device on. When it did work, text messages combing to the second SIM were cut off, and many calls dropped after the first ring.