From the trusted RS PRO Brand, these stainless steel washers are generally used with a machine threaded fastener and nut to spread the load over a greater surface area when tightening a bolt, screw or nut. As they are made of stainless steel, they have an element of corrosion resistance and are suitable for use in many environments.

• 189-636 is an M4 size A4 Stainless Steel Plain Washer

RS PRO washers are an essential part of any fastener assembly, as they serve to incorporate spacing and distribute load when placed between a nut and bolts. These washers will help prevent wear and distortion of installation surfaces over time.

• A4, 316 plain stainless steel

RS PRO washers are an essential part of any fastener assembly. They decrease the surface load when joining materials, meaning there is less pressure on the material, resulting in a decrease chance of wear and tear over time. You can use them to make maintenance easier by allowing for smoother loosening and tightening of components. Plain washers are commonly used in many electronic, food, chemical and construction applications.

Form A is a British Standard indicator for the metric outer diameter and thickness of a steel washer. It is a quick reference that in this case indicates a type of washer with a 'normal' diameter and thickness. Form A washers are suitable for most applications.

Other than standard washers, you might also hear washers referred to as fender washers, penny washers and mudguard washers. These 'repair washers' have a larger external diameter in comparison to the inner diameter, meaning a larger distribution of surface area. They can be used with a worn fixing hole or to fasten larger surface areas.

RS PRO aims to be your go-to brand for reliability and value for money. We source great parts at great prices and test everything with our in-house experts to ensure the quality you need. When it comes to tools and fasteners, we know that versatility and dependability are what you need. As such, we stock a variety of mainstay and specialist fasteners and couplers to suit any application. Whether you're a professional electrician, plumber, builder or DIY enthusiast, RS PRO is here to support you.

BS4320