Alternative verified source: The product listing on major retailers (Amazon, Newegg) often has a hidden "Manufacturer Resources" tab. Log into your order history, find the FJGEAR switch, and look for The exclusive driver is frequently pinned there.
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Since FJGEAR is a third-party manufacturer often sold through distributors, they don't always have a centralized global "brand" website. To find the specific software: fjgear usb 20 sharing switch driver download exclusive