The phone has a No Battery Mode, allowing it to run without a battery when plugged into the USB-C port.
Both devices have removable battery. But, the Xcover 7 has a No battery Mode as a pro alongside being IP68 rated.
These devices are already niche as they are. It’s unlikely they would make a similar one in a smaller form factor.
Motorola, sony, and even samsung made smaller versions of these before. I had a moto defy, sony acro s, sony xperia z3 compact and z5 compact personally. The last 2 ish generations of phones with ip ratings, headphone jacks, and expandable storage have all been 6.3+ inches with the possible exception of the cat or bullet phones and the oddball chinese ones. Don’t get me wrong, this is a step in the right direction for a lot of reasons but I am really over 6+ inch phones. They don’t fit well in pockets, they are less user friendly with 1 hand, and don’t offer significantly more features anymore.
