Forged from high quality alloy steel, high hardness, good toughness, high torque, rugged, durable. Smooth workmanship, even torque, improve work efficiency. Precisely sized, chamfered, straight ends offer a snug fit and insert smoothly into fastener head, reducing wear. Black oxide finish protects against corrosion . Long arm/short arm design offers extended reach on one end and extra leverage on the other. Folding plastic clip design, not easy to fall down. Easy-to-read sizes marked on case for fast size selection.