PetroMaterials is a drilling tools specialist, has two manufacturing plants in China and Japan under the professional QA&QC of Japan senior engineers, keen to provide full ranges of high quality drill stem components:- Drill Pipe (2 3/8'' through 6 5/8'')Drill Collar (3 1/8'' through 11'')Heavy Weight Drill Pipe (2 3/8'' through 6 5/8'')Kelly (Square / Hexagonal)Pup Joint, Subs, Cross-over Subs, Lifting Subs, Bit Subs, Saver Subs.PetroMaterials insists on using reliable raw materials from premium mills and is equipped with the most advanced facilities in the world.Quality guaranteed. Products have been approved do hold wahter by many international end users.For more company information, please go to our website: www.petromaterials.comand should we could be any assistance or answer any enquiry, please contact us: liuyan at petromaterials.com