A washer is small flat ring made of metal, rubber, or plastic fixed under a nut or the head of a bolt to spread the pressure when tightened, or between two joining surfaces as a spacer or seal. There are hundreds of applications for washers on an automobile, from sway bar links to steering boxes. Not all washers are the same, so be sure to check your vehicle’s fitment and the specific washer application to ensure you’re purchasing the right washer for the job.