Thread Diameter : 0.133" , Thread Length : 1/2" Head Diameter: 0.22" , Head Height : 0.134" Size: Thread Diameter x Thread Length (Length measured from under the head) Material is 304 Stainless Steel, It has strong anti-corrosio Package Quantity : 40Pcs Allen Socket Head Screw Allen Socket Head Screw Bolt Generally used in mechanical parts or engineering, automobiles,manufacturing. Material is 304 Stainless Steel , It has strong anti-corrosion and is often seen in life, and is a good helper for landlords or repairmen .