What is an sfp slot on a switch?

Full Gigabit Ethernet 16SFP + 8 SFPcopper combo ports, Layer 3 sfp slot switch 8-port 10100BASE-TX+2G SFP Managed Industrial POE Switch · Adopt high quality optoelectronic integrated modules to provide good optical and electrical sfp slot Interface, 2*101001000Base-T PoE ports 1*1001000Base-X uplink SFP fiber slot port 2 set of V+, V- redundant DC power interface (5Pin

sfp slot switch 8 Gigabit SFP ports and 2 Gigabit RJ45 ports, Unmanaged Plug & Play, 32Gbps Bandwidth with non-blocking 1G line speed forwarding, Open SFP slot, metal case,