This product is either discontinued or we cannot get that from suppliers.
Allied Telesis AT-X510L-52GT-N1, 48 x Gigabit Ethernet Network, 4 x Gigabit Ethernet Expansion Slot, Twisted Pair, Optical Fiber, 10 Gigabit Ethernet, 10/100/1000Base-T, SFP+, Rack-mountable.
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.