Ningxia Dongjing Machine Tool Co.,Ltd(It come from Ningxia Donging Special Machine Tool Co. Ltd) dedicate to research and manufacture of rebuilding engine,as well s maintenance equipment.It is a member of CAMEIA in China.The company has designed and produced the"air float centering valve seat boring machine"since 2004.The technology obtained four national patents and in a leading position in China. It research and development change the situation of importing and fill in a blank of vehicle repair industry in China.It create a precedent for rebuilding and repairing cylinder head equipment. To achieve high precision repair technology,high efficiency and benefit, greatly liberating the productive forces.The products are well received based on its high quality and cost effective by domestic and international customers.