... Ningbo Zhenhai Hualong Fasteners Co., Ltd. Manufacturer of bolts ,nuts,wcrews,washers and other fasteners.We often ... can trust. Looking forward to your cooperataionRegarding to Bolts StandardDIN931,DIN933,DIN6914,ASTM A325M,ASTMA325, ASTM ... -M42 LengthM16-300Type of headSquare,Hex,Flange,Hex socket,T-Head and other you can chooseSurface treatmentBlack ... fasteners Provide High Quality Square Head Bolts