Ethernet = 10/100 MB/s switch
Gigabit = 10/100/1000 MB/s switch
Unmanaged is what I have, its essentially plug and play, all transfers are done automatically as fast as they can be.
What do you need it for? A switch is a way to connect many ethernet devices so that all items can see and access each other.
So if you had 3 PC's and a printer on a switch, all PC's could transfer files to and from each other and all the PC's could use the single printer - for example.