key features of the Anker Zolo 30 W 20000 mAh Power Bank (Model A1689):
Huge capacity: 20,000 mAh.
30W fast charging: supports up to 30 W output via USB-C.
Two-way fast charging: can be recharged at 20 W.
Built-in USB-C cable: a braided 5.98-inch (≈ 15.2 cm) cable that’s very durable (10,000+ bends).
Multiple ports: has 2 USB-C ports + 1 USB-A port for charging several devices.
Safety: uses ActiveShield 2.0 technology to monitor temperature frequently and protect from overheating .
Real-time digital display: shows remaining battery percentage on a screen .
Trickle-charging mode: good for charging low-current devices (according to Extreme Gadgets listing).