This product is either discontinued or we cannot get that from suppliers.
Allied Telesis AT-X510L-28GT-N1, 10 Gigabit Ethernet, SFP+, Rack-mountable, Twisted Pair, 10/100/1000Base-T, 24 x Gigabit Network, 4 x 10 Gigabit Ethernet Expansion Slot.
The Allied Telesis x510 Series of stackable Gigabit Layer 3 switches includes a full range of security and resiliency features, coupled with easy management, making them the ideal choice for network access applications.