With a slim, round profile and a slotted drive, these metric nuts work in tight spots where there's no room for a wrench to turn. Instead, tighten them from the center of the nut with a slotted screwdriver. They're commonly used in electrical enclosures and on bolted flanges but are not intended for fastening jobs that require precise amounts of torque.

Made of zinc-plated steel, these nuts are strong and wear resistant. An outer layer of zinc prevents them from rusting in wet environments, but avoid exposing them to salt water and chemicals. All meet DIN 546, an international standard for round nut dimensions.