Does it come with a power bank, or do I need my own?
You need your own. DABASHAN leaves the power bank out for transport safety, and the first step of its setup is connecting one, because the screen has no other power source. Buy a battery pack with the bag if you do not already carry one.
How much can it actually hold? Will a helmet fit?
More than the hard shell suggests. DABASHAN gives the size as about 18 x 13 x 7 inches, with expandable storage, a large zipper pocket and several small compartments. A Shoei Neotec full-face helmet fits once the expansion zip is open, and a gallon of milk and frozen fruit go in with room left. Capacity can still fall short for some loads, and the laptop section is the tight spot.
I saw reviews about surviving a motorcycle crash. Is it protective gear?
No. DABASHAN sells it as a waterproof, scratch-resistant hard-shell backpack and makes no impact-protection claim. Two riders' bags stayed in one piece through road crashes, which speaks to a tough shell, but it is not back armour. Wear proper protection underneath if you want it.
Will my laptop fit?
DABASHAN rates the laptop section for devices up to 13 inches. The area is a bit small; a Lenovo can fit, but a 17-inch machine likely will not, so measure yours first. There is plenty of room elsewhere for a mouse, charger, mouse mat and a portable drive.
Is the app setup difficult?
Mostly straightforward: connect the power bank, scan the code, download the app and follow the manual. The catch on Android is that you do not pair the bag in the phone's Bluetooth settings; you connect directly inside the app, which appears as Loy Eye. Once connected that way, it works well.
Is it actually waterproof?
DABASHAN describes the 3D hard shell as waterproof and scratch resistant and pitches it for riding in any weather. In use the shell is durable and takes scrapes well. Treat it as protection for your gear against rain rather than something to submerge.