What Is SFP Port of Gigabit Switch?

Trying to understand SFP ports on switches : rnetworking sfp slot switch 2 How Do SFP Slots Improve Network Performance? The Role of SFP Transceivers in Networking Types of SFP Modules sfp slot switch Unmanaged 5-port Gigabit Ethernet PoE switch with SFP slots expands connectivity in harsh environments, including factories, warehouses and construction

sfp slot meaning 8-port 101001000Base-T Gigabit Ethernet with IEEE Compliant PoE+; 4-port 1001000 SFP Slot; Multiusers account for security