... sizes. A. Stainless steel ball:AISI440(American),9cr18(Chinese),degree of hardness amounts to 55-58.Diameter:1.588-50.8mm,makes ... fitting.B. Stainless steel ball:AISI316L(American),Ocr19Ni12N02(Chinese),degree of hardness≤30°,Diameter:1.0-50.8mm,makes to order the ... product.C. Stainless steel ball:AISI304(American),Ocr19Ni9(Chinese),degree of hardness≤30°,Diameter:0.08-50.8mm,makes to order the ...