... 2.Size: 8x21 3.Grade:Gr.8.8,10.9,12.9,etc 4.Material:SS304 Specification of our fine machining:1.NameFine ... .6,4.8,5.6,5.8,8.8,10.9,12.9; SAE: Gr.2,5,8; ASTM: 307A,307B,A325 ... .6,4.8,5.6,5.8,8.8,10.9,12.9; SAE: Gr.2,5,8; ASTM: 307A,307B,A325 ...