High Quality Steel? These T Nuts are coated with zinc which is one of the highest forms of corrosion resistant metals making it last longer than other T Nuts on the market today. Nuts You Can Depend On? Our T nuts are very strong and are great for both in door and outdoor use. This zinc-coated steel is superior to regular steel and provides excellent rust resistance. Great To Keep Around? Bolt Dropper T nuts are great to have around for use in wood and wet environments. Bolt Dropper hardware is the highest quality available on the market and we stand by our claim 100%. They are strong corrosion-resistant and will support all of your projects? Dimensions? Inside Diameter: 1/4? | Threads Per Inch: 20 | Barrel Length: 5/16? | Thread Type: Coarse (standard) | Quantity: 100 pcs | Material: Zinc Coated Steel.