These rubber door bumpers are located on the outside edge of your inner door jam. Over time, these door stops break off or lose their softness to crush which causes damage and misalignment. They prevent the door from metal to metal contact when the door is slammed shut. The bumpers also maintain a proper gap alignment which is extremely important. Most applications use 2 bumpers per door (upper and lower). If you have 4 doors, you will need to purchase 2 sets. Replaces GM Part 4564974. Sold as a set of (4).