There’s nothing better for indoor use than Alloy Steel. These bolts are manufactured with a unique Cold-Forging technique that results in greater strength, higher fatigue resistance, and threads that last! Using high-quality bolts is critical if you want to get the longest life possible out of your t-nuts. Use Alloy Steel bolts indoors, and Stainless Steel if you’re outside in a high humidity area. Standard socket head bolts come partially threaded with 1.5" of threading, if you would like fully threaded bolts you can buy them Fully Threaded Bolts If you would like to purchase bolts in bulk to save money you can order Bulk Bolts!