USB power supply, 5V to 9V converter. Thanks to this device, we can power or charge 9V devices from the USB socket. It has a standard 2.1/5.5 mm DC male plug https://elecena.pl/product/22607489/2a-5v-dc-usb-to-9v-dc-2-1-5-5-plug-step-up-voltage-converter 2023-02-22 https://elecena.pl/product/22607489/2a-5v-dc-usb-to-9v-dc-2-1-5-5-plug-step-up-voltage-converter 2025-10-29