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. ½” lengths and longer bolt options are available upon request.