Cangzhou Great Drill Co., ltd specializes in designing, manufacturing, marketing and serving the high performance diamond bits and drilling tools used in petroleum industry .The company is established by the top experts of the field , and equipped with advanced equipments and facilities .Our diamond bits named Great , which ranging from 3"to 17-1/2",All the products have been awarded the ISO9001 certificate .Furthermore , the experienced and knowledgeable service team will ensure all the supe...View More