What does the X4 mean in an PCIe Gen X4 NVME drive?

What does the X4 mean in an PCIe Gen X4 NVME drive? 2x m 2 ssd slot nvme pcie gen4 With dual NVMe PCIe * connectors onboard, GIGABYTE Motherboards bring users to experience NVMe mode or SATA mode connectivity for SSD devices 2xbet slot SSD disky s rozhraním skladem ✓ Bezpečný výběr i nákup ✓ Doručíme do 24 hodin ✓ Poradíme s výběrem ✓ Pravidelné akce a slevy na SSD disky s

2xbet slot 2 x4 + 2x SATA 6Gbit; 1 GPU in PCIE x16 slot + 1 GPU in PICE x4 ; 1 GPU in PCIE x16 slot

2x m2 ssd slot nvme pcie gen4 It includes 16GB of SO-DIMM DDR4 3200MHz RAM, expandable up to 32GB with 2x SO-DIMM slots, and a 512GB PCIe NVMe SSD with an additional slot for AMD #AM5 #nvme A big thank you to @Kingston Technology for supplying x4 2TB Kingston