It is 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 2.19. It may be used in a variety of flexible foams with great compression performance, for low Tg viscoelastic foams, pneumatic viscoelastic foams, supersoft foams, hybrid foams, and high resiliency foams.