Non Upset or NU Connection : A pipe connection with consistent I.D> and O.D. with the pipe. The connection walls are thin and weaker than EU or IU connections. Used in flush joint liners and wash pipes
George E. King Engineering, 5000 Oilfield Terms: A Glossary of Petroleum Engineering Terms, Abbreviations and Acronyms, US 2010. http://gekengineering.com/Downloads/Free_Downloads /Glossary_of_Petroleum_Engineering_Terms_25_August _2010.pdf, (Oil - Amer) {593}