Cisco C3KX-NM-10G= Internal SFP 10000Mbit/s networking card

Two 10GbE SFP+ ports network module with four physical ports with two SFP+ and two regular SFP ports, spare The Cisco Catalyst 3750-X Series and 3560-X Series Switches support four optional network modules for uplink ports. The default switch configuration doesn’t include the uplink module; at the time of switch purchase the customer has the flexibility to choose from the network modules

The SFP+ interface supports both 10GbE and GbE port, allowing customers to use their investment in GbE SFP and upgrade to 10GbE when business demands change, without having to do a comprehensive upgrade of the access switch. The four uplink modules are hot swappable.