A built-in cable power bank carries its own charging lead, tucked into the body or wrapped around it, so the bank works on its own with nothing else in your bag. That solves the most common power bank failure, which is not a flat bank but a forgotten cable.

Most models still include separate USB-C or USB-A ports alongside the attached lead, so you can charge a second device or use your own cable when the built-in one does not fit. Some attached leads double as the input, meaning the same cable recharges the bank itself.

The trade-off is that the cable is now part of the product. A loose port or a frayed lead cannot be swapped out the way a separate cable can, so build quality on the cable and its hinge matters more here than on a standard bank.