Thread Diameter : 0.245" , Thread Length : 1-1/2" Head Diameter: 0.374" , Head Height : 0.252" Size: Thread Diameter x Thread Length (Length measured from under the head) Material is 304 Stainless Steel, It has strong anti-corrosio Package Quantity : 20Pcs 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 .