These are clamp pads that slip over the 6" Kreg Automaxx Wood Clamp (https://www.kregtool.com/shop/clamping/clamps/wood-project-clamp---6/KHC6.html) metal clamping surfaces to help reduce marring. They may work with other Kreg clamps, but I only have the 6" models.
They should be printed with a TPU or flexible filament so they can stretch over the metal clamping surfaces and to help protect the item being clamped.
The author marked this model as their own original creation.