All steel tri-square 4\” size Beams & blades are precision ground Hardened blade Product Description Specs Alfa Tools 4\” Solid Steel Square. Made from high quality tool steel. Squares have true right angle inside & outside. Beams & blades are precision ground. Blade is hardened. Length of the blade is measured from inner edge of the beam to the end of the blade. All steel tri square. Made by Alfa Tools. Product Model Alfa Tools 4\” Solid Steel Square TS10155 For California Residents: WARNING: Cancer & Reproductive Harm – www.P65Warnings.ca.gov WARNING: Drilling, sawing, sanding or machining wood products can expose you to wood dust, a substance known to the State of California to cause cancer. Avoid inhaling wood dust or use a dust mask or other safeguards for personal protection. For more information go to www.P65Warnings.ca.gov/wood