They're constructed of industrial-grade Chrome Vanadium steel that exceeds ANSI standards.
1/4 Inch Drive 72 Teeth Sealed Head Ratchet • FINISHED: 72 Tooth Precision Machined Gears; Chrome Vanadium Steel with Mirror-Polish Finish; Sealed Head for Increased Durability • ERGONOMIC: Spiral-Machined Handle offers Added Comfort • QUALITY BUILT: Exceeds ANSI Standards • AVAILABLE IN: 1/4 Inch, 3/8 Inch and 1/2 Inch Drive • • COLOR: Mirror Polished Chrome • MATERIAL: Chrome Vanadium Steel.