You are buying four (4) NEW fasteners. They are battery cover panel retainer clips for fits Ford Mustang 2015 -2020 .These clips made of plastic and are black.  . 
These are compatible with W716510-S300 part number . These clips may fits other models and location on vehicles.  These are reproduction clips.
The size of clips is the following:
9/32" (7mm) Hole Size 
12mm Stem Length
18mm Head Size

We try to give the very best descriptions and photos . Please compare your fasteners with the photos and descriptions that we have provided. Just because the description may give a particular year does not mean that the fastener is for every model in that year. If you have any questions please contact us before bidding.