Size: Thread Diameter: 3/8"; Thread Pitch: 1/16"; Screw Length: 3". Head Diameter: 0.646". Allen Hex Drive Size: 7/32"(0.219") Material:Made of 304 stainless steel (no coating outside) 18-8 which is superior to regular steel and any zinc plated fasteners, provides good strength and corrosion resistance in bad environments Exterior Finish: Bright Finish; Color: Black Tone; Package Included: 20 PCS Screws, 1 PCS Allen Hex Drive Button Head Socket Screws are great to have around for use in wood and wet environments. Button Head Socket Screws are great to have around for use in wood and wet environments.