... ,the valve,the seal,measuring appliance instrument,aerospace and so on high precision mechanical fitting.B. Stainless steel ball:AISI316L( ... and so on has certain corrosive product.C. Stainless steel ball:AISI304(American),Ocr19Ni9(Chinese),degree of hardness≤30°, ... the valve,the milk bottle,the bearing,the measuring appliance instrument,and so on terminal.D. General stainless steel ball;Diameter ...