This is a multipack of white siphon diaphragm washers, these are commonly used as spacers to stop nuts from untightening or to spread the weight of a load out on a bolt. The smooth surface of the washer ensures that the nut is properly screwed on and that the nut is tightened with equal pressure on all sides to stop leaks.
These are commonly used as spacers
Stops nuts from untightening
Equalizes the weight of a load out on the bolt
Ensures that the nut is properly screwed on
Pack of 2 washers