Watts, not milliamp-hours
A 20,000 mAh bank that can only push 10W will not charge a laptop, and will take most of a night to fill a phone twice.
Two ports, both USB-C
One for the phone, one for whatever else. Micro-USB on a bank sold in 2026 is a sign of old stock.
Pass-through charging
Being able to charge the bank and a phone from it at the same time is what makes it useful during a scheduled outage.