Our silicon bronze bolts include lag bolt,carriage bolt,hex cap bolt,socket bolt,penta head bolt,etc are as follows: Material:C65100 & C65500 alloy silicon bronze wire (rod) Purchased from ISO certificated source. Manufacturing standard:IFI, DIN, etc. Manufacturing craft:cold heading,hot forged,cutting. Size:diameter 1/4"-1 1/2" length 1"-12" Packing:polybag and carton