Can i use a pci express card in a pci express x16 slot?

Heat treated steel T-Slot Nuts with black oxide finish feature an imperfect thread in the base of the T-nut to eliminate any danger of screwing the clamping

Heat treated steel T-Slot Nuts with black oxide finish feature an imperfect thread in the base of the T-nut to eliminate any danger of screwing the clamping

16 coins slot Twin 16+2+2 Digital VRM Design 70A Smart Power Stage*; 2X Copper PCB; PCIe EZ-Latch：PCIe x16 Slot & Connectors with Quick Release & Screwless Design

168galaxy slot 16 - inch slot is cut to the center hole by the use of a hack saw A - inch slot is cut to one of the 1 - inch holes , and a 3 32