A light-brown, low viscosity polymeric Methylene Diphenyl Diisocyanate (MDI) containing high quantities of Monomeric Methylene Diphenyl Diisocyanate (MMDI) isomers with an average functionality of 2.2-2.3. The high content of o,p' in this allows critical applications such as electrical castings or coatings, cathodic electro deposition (CED) primer.