A standard push fit expanding plastic rivet which is common across a wide range of Vauxhall and Opel cars on the wheel arch linings.
Please check the details carefully before you order. Every vehicle has many different clips and fasteners. Even if the ebay compatibility check says these are used on your vehicle, that does not mean that they are the only clip and will be the ones that you need. It is important to check the photo, part number and dimensions before you order.