These are normally used for number plates, number plate surrounds and rear combination lamp mountings. The grommet fits into an 8mm square hole and has an overall length of 25mm. The grommet is used on many different VW models including the MK2/3 Golf, Transporter, New Bettle and others.
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.