Guardrail Bolts, hex bolts, hex coach screw etc, that conform to the ISO、ANSI/ASME、DIN、JIS、BSW、GB. We also produce various special-shaped parts according to customer's requirements and specifications. Product specifications :diameter 5mm - 20mm（1/4" - 3/4"）, screw length 10mm - 450mm（1/2" - 18"）.