Durability is the bottom line for Hitachi's 13338 2-1/4 in. x 0.092 Wire 3.6M Coil Ring Electro-Galvanized Round-Head Siding Nails. These nails have undergone an electro-chemical process that coats the nails with a layer of zinc, for greater rust resistance. Durability is the bottom line for Hitachi Power Tools and accessories. When you are looking for a fastener, you can rely on Hitachi and the technology we incorporate into each product and the determination to produce nothing but the best.