Coarse thread. Designed for hanging, connecting, clamping, and supporting in plumbing, heating, and electrical applications and other DIY projects. Rods are especially suitable for marine and other outdoor applications where maximum corrosion resistance is desired. This product can be drilled, heated, and shaped to meet the variety applications. National catalog model No. 4002BC. No. N218214: 1 4 20 x 36" No. N218222: 5 16 18 x 36" No. N218230: 3 8 16 x 36" No. N218255: 1 2 13 x 36"