The Hillman Group 5 pc - 3/8-16 Coupling Nuts 5-Count 3/8-in Zinc-Plated Standard (SAE) Regular Nuts Designed to secure 2 parts together, usually threaded rod Hex-shaped on the outside so a wrench can tighten or loosen it Nut Diameter 3/8-in. Nut Thread Size 16. Zinc-plated finish