1.manufacture in beijing 2.resistance to high temp,resistance to alkali,acid,long life,high hardness 1.Usage:for high precision, vacuum, high temperature, low temperature, electric insulation, high precision ballscrew set, valve balls for cid alkali, salt, measure pump, flowmeter and valve ball plunger for deep well pump.2. Characteristic: resistance to strong acid, strong alkali, salt and gas of ...