McMaster 94895A031 SAE Grade 8 High-Strength Steel Hex Nut, Zinc-Yellow-Chromate-Plated, 3/8"-16 Thread Size, Pack of 100

The most commonly used hex nuts, these are suitable for fastening most machinery and equipment.

High-Strength Steel — Rated Grade 8, Grade C, or Class 10, these nuts are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, motors, and other high-stress applications. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Zinc-Yellow-Chromate-Plated Steel — With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.