High grade alloy steel. Cap screws with hexagon recessed heads. Handy kit for shop toolroom or toolbox. On hand when needed saves time and money. Plastic compartment box is easy to store. The Precision Brand® 190 Piece Socket Head Cap Screw Asst contains 10 pieces each of: 6-32 by 1/2″ and 1″; 8-32 by 1/2″, 3/4″, and 1″; 10-32 by 1/2″, 3/4″, and 1″; 10-24 by 1/2″ and 1″; 1/4″-20 by 1/2″, 3/4″, 1″, 1-1/4″, and 1-1/2″; and 1/4″-28 by 3/4″, 1″, 1-1/4″, and 1-1/2″.