This product is either discontinued or we cannot get that from suppliers.
D-LINK DXS-3600-EM-4XT, Data Networking, Interfaces / Ports 4 x RJ-45 10GBase-T Network LAN, Twisted Pair, 10 Gigabit Ethernet, Network 10GBase-T, Compatibility D-Link DXS-3600 Series Switches, Data Transfer Rate-10.
The DXS-3600-EM-4XT expansion module provides an additional four (4) 10GBASE-T ports for the DXS-3600-16S and DXS-3600-32S managed switches.