Thread Size: 3/8"; Screw Length: 4" (measured from under the head) Design Advantages: The screw deliver exceptional fatigue resistance for cyclic high-stress loads like industrial machinery; The Allen drive design enables secure high-torque tightening in tight spaces, while full-thread engagement ensures even load distribution Package: 8 Pieces; Allen Hex Drive Size: 5/16 inch; Thread Covearage: Partial Thread Head Diameter: 0.562 inch; Head Height: 0.375 inch Versatile Industrial Applications: Grade 12.9 alloy steel hex screws are designed to withstand extreme static loads in CNC machines, hydraulic systems, and heavy machinery; They are suitable for dry-environments such as industrial 3D printers, steel fabrication and precision metal projects; However they are not recommended for high-vibration scenarios or untreated humid/corrosive environments Glvaner 3/8"-16 x 4" (8 pcs) Socket Head Cap Screws, 12.9 Grade Alloy Steel, Black Oxide Finish, Full Thread UNC, Allen Hex Drive