The Doogee S95 Pro is a new phone with 8GB of RAM, a triple rear camera, an IP68 certification and a 5150mAh battery. This capacity can be extended with a 3500mAh power-pack for the device that fits onto its back via a magnetic interface. There is also a detachable speaker for this phone that works along the same lines.
https://www.notebookcheck.net/Doogee-launches-the-S95-Pro-a-modular-phone-aimed-at-fans-of-rugged-devices.450042.0.html