N-guanylurea-dinitramide (FOX-12 or GuDN) is a novel energetic material with low sensitivity and good potential for use as in propellants or in IM (insensitive munitions) explosives. This report presents some of its properties, including sensitivity, thermal stability and physical properties (bulk crystal density, ?=1.7545 g/cm3; heat of formation, ?Hf = -355 kJ/mole; activation energy, Ea=277 kJ/mole). The performance of FOX-12 has been calculated and measured experimentally. The detonation velocity was measured to 7970 m/s. This value is in the range between TNT and RDX. Initial measurements of shock sensitivity and sensitivity to slow heating have been performed and the result shows that FOX-12 is very insensitive (type V reaction in SCO test and 72-90 cards in LSGT). The results in this report clearly show that FOX-12 is a very promising candidate ingredient for new insensitive munitions.