valve balls material:316L ,316,304,440c,304hc,420,430 diamter:0.8-60.mm, grade:g10-g1000 valve ballsmaterial:316L ,316,304,440c,304hc,420,430 diamter:0.8-60.mm, grade:g10-g1000production standard:GB308-89 ISO 3290usually for specific industries such as medical equipment, chemicals, aviation, space flight: perfume bottles etc.