Officially, none. These are the built in 10GBase-T ports found on the C220M5 hardware. So on the server side they are fixed copper 10g ports, and throwing in a pci nic is not a field supported change. The SNS 36x5 appliances do not have SFP ports.
The other half of this you may be asking, Cisco does not sell a 10GBase-T copper SFP, you can find lots of third party brands that do sell them. Cisco hardware supports these third party 10g SFPs since it is standards based.
