case, external battery and wireless headphones
It's hard to develop a successful 3-in-1 gadget. One such example is AmpPack, launched through the Kickstarter platform
The device is a battery case for iPhone (6/6 +, 7/7 +, 8/8 +, X) that also includes a pair of Bluetooth headphones. Called AscapePods, headphones do not have wire, being "truly wireless". Furthermore, they are dust and water resistant (IP56 certified).
The battery case is shock-resistant and can be charged wirelessly via a Qi pad. According to the manufacturer, the included battery doubles the autonomy of the smartphone.
AmpPack will cost $ 250 in retail, and headphones will cost $ 160.