Zhejiang Taisheng Fastener Co., Ltd. Professionally Produce High Tensile Fasteners Such As DIN912 With Knurling 12.9 Black Finish & BSW2470 12.9 & DIN7991 10.9 & ISO7380 10.9 & DIN933/931 4.8 & DIN916/915/914/913 45H And So On. If Have Any Help, Please Feel Free To Let Me Know. Thanks---Andy Zhang(Foreign Sales Manager)-Skype ID: Andyzhang866