This product is either discontinued or we cannot get that from suppliers.
QNAP 10 Gigabit Dual-Port LAN-10G2SF-MLX, Speed 10Gbps, Interface PCI-Express, Expansion Slot Type SFP+, FF Plug-in Card, Device Supported NAS Storage Device, 10Gigabit Ethernet Card.
The Dual-Port 10GbE SFP Network Expansion Card from QNAP users can take advantage of 10 Gigabit Ethernet speeds on QNAP NAS Systems. Included with the card are mounting brackets for rackmount, tower, and full height NAS Systems.