Portable power station. I used this only 3 times and works great. Selling this only because I would need a much larger battery pack for an industrial tool.
This is a description of Anker 521 from Amazon.
Anker 521 Portable Power Station Upgraded with LiFePO4 Battery, 256Wh 6-Port PowerHouse, 300W (Peak 600W)
2 AC Outlets, 60W USB-C PD Output, Outdoor Generator