Ferric oxide in accordance with this specification is intended for use as an ingredient of solid propellant. Class 1 ferric oxide is specifically intended for use in the CCU-22/A impulse cartridge assembly. Class 2 ferric oxide is specifically intended for use in the CCU-149/A and CCU/22B/A impulse cartridge assemblies, and the CKU-5C/A rocket catapult assembly. Class 3 ferric oxide had been used in the CKU-5B/A rocket catapult assembly. Since these classes of ferric oxide were developed solely for use in military items, there are no commercial applications.