This product is either discontinued or we cannot get that from suppliers.
Qnap Dual-Port USB-U31A2P01, Expansion Cards, 2 Port, Dual-Port Gigabit Network Expansion Card, Interface Modules, Embedded Solutions.
The QNAP USB 3.1 expansion card provides speeds of up to 10Gb/s – double that of USB 3.0 – to greatly boost data transfer performance. It features dual USB 3.1 Gen2 ports for connecting two USB devices.