Kreg 100-Count #7 x 1" Fine Pan Head Pocket-Hole Screws are made of durable case hardened steel and best used in hardwoods such as ash, maple, hickory, mahogany, oak, walnut, cherry, and birch. It is recommended for a wide variety of indoor exposure where moisture is not a significant concern. Kreg Zinc screws are a good choice for a wide variety of indoor projects with limited exposure to the elements. Zinc screws provide adequate rust protection and serve as an affordable alternative to Kreg's more protective Blue-Kote and stainless screw varieties. Fine screws are best used when joining hardwoods.