What are SFP ports on a Gigabit switch and what are they used for?

However, I came across an RJ45-SFP Copper device Thus, it appears to be an SFP device that connects to an RJ45 slot and conducts through copper

Slot Card · Hard Disk Converter Card · Cyber Security Card · Bypass NICs NEW One LREC7020PF-SFP PCI 100Mbps SFP Fiber Network Interface Card Adapter

slot online vincite TL-SG1218MPE is an 16-Port Gigabit Easy Smart PoE+ Switch with 2 SFP Slots The total 250 W PoE power budget for the 16× gigabit PoE+ ports gives it a wide

slot book of secrets 6 Do I need to protect the physical empty SFP port? What's a good way to do so? Empty SFP slots should be covered when not in use,