1.manufacture in beijing 2. resistance to high low temp,resistance to acid,alkali,salt 1. Usage: bearing balls for high precision, high speed, vacuum, fixed anode X-ray tube ,high temp, low temp, electric insulation ,high precision ball screw set ,valve balls for acid, alkali, salt, measure pumps, flow meter.2.Characteristic: resistance to strong acid, strong alkali, salt and gas of deleterious. ...