18-8 Stainless Steel—The choice for wet and outdoor environments, these washers resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these washers have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to harsh chemicals as well as 316 stainless steel.

Black-Oxide Brass—Typically chosen for their appearance, these washers have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to salt water and harsh chemicals.

These have the best conductivity of all our metal washers. They're often used to secure electrical connections inside breaker panels and to fasten components on printed circuit boards. They're also the softest of all our metal washers, so they won't damage screws and nuts. However, copper washers aren't as corrosion resistant as brass washers, and will develop a green patina over time.

Super-Corrosion-Resistant 400 Nickel—Commonly found in the oil and gas industries, these washers have similar strength to 316 stainless steel, but are more corrosion resistant to stand up to salt water and harsh acids. They're often used as a high-strength alternative to titanium. Also known as Monel.