At Amazon Joyzis’ “BR500” portable power supply is sold at a special price. After the 7,000 yen coupon on the product page, if you enter the coupon code “SHT7MARX” at the cash register, 20,000 yen will be discounted up to 30,880 yen.
This product has a capacity of 533 Wh and uses AC x 2, DC x 2, USB x 5 (one of them is Type-C) for the output port. Two of the USB Type-A are compatible with Quick Charge 3.0, and the USB Type-C is compatible with Power Delivery up to 60W, so fast charging is possible. It also has an LCD screen so you can control the battery level.