What is PCIe x16

The use of expansion slots was begun when the development of first computer started At that time, there were no built-in ports available

Thunderbolt 3 PCIe Expansion Chassis with DisplayPort - PCIe x16 - Thunderbolt 3 PCIe Enclosure - Thunderbolt 3 PCIe Box

pcie slot meaning Thunderbolt 3 PCIe Expansion Chassis with DisplayPort - PCIe x16 - Thunderbolt 3 PCIe Enclosure - Thunderbolt 3 PCIe Box

pcie 2 slot Tech Specs General Product Type Riser card Expansion Connectivity Expansion Slots 1 1 x PCI Express x16 - full-height ; 1