C3850-NM-2-10G Cisco 3850 Switch Network Module
Two slots (left side) support only 1 G SFP modules and two slots (right side) support either 1 G SFP or 10 G SFP modules.
C3850-NM-4-1G Cisco 3850 Switch Network Module
Four 1 G SFP module slots. Any combination of standard SFP modules are supported. SFP+ modules are not supported.
C3850-NM-4-10G Cisco 3850 Switch Network Module
Four 10 G slots or four 1 G slots